diff --git a/backend/internal/handler/admin/account_handler.go b/backend/internal/handler/admin/account_handler.go
index ac938f8c..f2d8a287 100644
--- a/backend/internal/handler/admin/account_handler.go
+++ b/backend/internal/handler/admin/account_handler.go
@@ -3,6 +3,7 @@ package admin
 import (
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/Wei-Shaw/sub2api/internal/handler/dto"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/claude"
@@ -13,6 +14,7 @@ import (
 	"github.com/Wei-Shaw/sub2api/internal/service"
 
 	"github.com/gin-gonic/gin"
+	"golang.org/x/sync/errgroup"
 )
 
 // OAuthHandler handles OAuth-related operations for accounts
@@ -989,3 +991,164 @@ func (h *AccountHandler) GetAvailableModels(c *gin.Context) {
 
 	response.Success(c, models)
 }
+
+// RefreshTier handles refreshing Google One tier for a single account
+// POST /api/v1/admin/accounts/:id/refresh-tier
+func (h *AccountHandler) RefreshTier(c *gin.Context) {
+	accountID, err := strconv.ParseInt(c.Param("id"), 10, 64)
+	if err != nil {
+		response.BadRequest(c, "Invalid account ID")
+		return
+	}
+
+	ctx := c.Request.Context()
+	account, err := h.adminService.GetAccount(ctx, accountID)
+	if err != nil {
+		response.NotFound(c, "Account not found")
+		return
+	}
+
+	if account.Platform != service.PlatformGemini || account.Type != service.AccountTypeOAuth {
+		response.BadRequest(c, "Only Gemini OAuth accounts support tier refresh")
+		return
+	}
+
+	oauthType, _ := account.Credentials["oauth_type"].(string)
+	if oauthType != "google_one" {
+		response.BadRequest(c, "Only google_one OAuth accounts support tier refresh")
+		return
+	}
+
+	tierID, extra, creds, err := h.geminiOAuthService.RefreshAccountGoogleOneTier(ctx, account)
+	if err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	_, updateErr := h.adminService.UpdateAccount(ctx, accountID, &service.UpdateAccountInput{
+		Credentials: creds,
+		Extra:       extra,
+	})
+	if updateErr != nil {
+		response.ErrorFrom(c, updateErr)
+		return
+	}
+
+	response.Success(c, gin.H{
+		"tier_id":             tierID,
+		"storage_info":        extra,
+		"drive_storage_limit": extra["drive_storage_limit"],
+		"drive_storage_usage": extra["drive_storage_usage"],
+		"updated_at":          extra["drive_tier_updated_at"],
+	})
+}
+
+// BatchRefreshTierRequest represents batch tier refresh request
+type BatchRefreshTierRequest struct {
+	AccountIDs []int64 `json:"account_ids"`
+}
+
+// BatchRefreshTier handles batch refreshing Google One tier
+// POST /api/v1/admin/accounts/batch-refresh-tier
+func (h *AccountHandler) BatchRefreshTier(c *gin.Context) {
+	var req BatchRefreshTierRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		req = BatchRefreshTierRequest{}
+	}
+
+	ctx := c.Request.Context()
+	accounts := make([]*service.Account, 0)
+
+	if len(req.AccountIDs) == 0 {
+		allAccounts, _, err := h.adminService.ListAccounts(ctx, 1, 10000, "gemini", "oauth", "", "")
+		if err != nil {
+			response.ErrorFrom(c, err)
+			return
+		}
+		for i := range allAccounts {
+			acc := &allAccounts[i]
+			oauthType, _ := acc.Credentials["oauth_type"].(string)
+			if oauthType == "google_one" {
+				accounts = append(accounts, acc)
+			}
+		}
+	} else {
+		fetched, err := h.adminService.GetAccountsByIDs(ctx, req.AccountIDs)
+		if err != nil {
+			response.ErrorFrom(c, err)
+			return
+		}
+
+		for _, acc := range fetched {
+			if acc == nil {
+				continue
+			}
+			if acc.Platform != service.PlatformGemini || acc.Type != service.AccountTypeOAuth {
+				continue
+			}
+			oauthType, _ := acc.Credentials["oauth_type"].(string)
+			if oauthType != "google_one" {
+				continue
+			}
+			accounts = append(accounts, acc)
+		}
+	}
+
+	const maxConcurrency = 10
+	g, gctx := errgroup.WithContext(ctx)
+	g.SetLimit(maxConcurrency)
+
+	var mu sync.Mutex
+	var successCount, failedCount int
+	var errors []gin.H
+
+	for _, account := range accounts {
+		acc := account // 闭包捕获
+		g.Go(func() error {
+			_, extra, creds, err := h.geminiOAuthService.RefreshAccountGoogleOneTier(gctx, acc)
+			if err != nil {
+				mu.Lock()
+				failedCount++
+				errors = append(errors, gin.H{
+					"account_id": acc.ID,
+					"error":      err.Error(),
+				})
+				mu.Unlock()
+				return nil
+			}
+
+			_, updateErr := h.adminService.UpdateAccount(gctx, acc.ID, &service.UpdateAccountInput{
+				Credentials: creds,
+				Extra:       extra,
+			})
+
+			mu.Lock()
+			if updateErr != nil {
+				failedCount++
+				errors = append(errors, gin.H{
+					"account_id": acc.ID,
+					"error":      updateErr.Error(),
+				})
+			} else {
+				successCount++
+			}
+			mu.Unlock()
+
+			return nil
+		})
+	}
+
+	if err := g.Wait(); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	results := gin.H{
+		"total":   len(accounts),
+		"success": successCount,
+		"failed":  failedCount,
+		"errors":  errors,
+	}
+
+	response.Success(c, results)
+}
diff --git a/backend/internal/handler/admin/gemini_oauth_handler.go b/backend/internal/handler/admin/gemini_oauth_handler.go
index 4440aa21..037800e2 100644
--- a/backend/internal/handler/admin/gemini_oauth_handler.go
+++ b/backend/internal/handler/admin/gemini_oauth_handler.go
@@ -46,8 +46,8 @@ func (h *GeminiOAuthHandler) GenerateAuthURL(c *gin.Context) {
 	if oauthType == "" {
 		oauthType = "code_assist"
 	}
-	if oauthType != "code_assist" && oauthType != "ai_studio" {
-		response.BadRequest(c, "Invalid oauth_type: must be 'code_assist' or 'ai_studio'")
+	if oauthType != "code_assist" && oauthType != "google_one" && oauthType != "ai_studio" {
+		response.BadRequest(c, "Invalid oauth_type: must be 'code_assist', 'google_one', or 'ai_studio'")
 		return
 	}
 
@@ -92,8 +92,8 @@ func (h *GeminiOAuthHandler) ExchangeCode(c *gin.Context) {
 	if oauthType == "" {
 		oauthType = "code_assist"
 	}
-	if oauthType != "code_assist" && oauthType != "ai_studio" {
-		response.BadRequest(c, "Invalid oauth_type: must be 'code_assist' or 'ai_studio'")
+	if oauthType != "code_assist" && oauthType != "google_one" && oauthType != "ai_studio" {
+		response.BadRequest(c, "Invalid oauth_type: must be 'code_assist', 'google_one', or 'ai_studio'")
 		return
 	}
 
diff --git a/backend/internal/pkg/geminicli/drive_client.go b/backend/internal/pkg/geminicli/drive_client.go
new file mode 100644
index 00000000..a6cbc3ab
--- /dev/null
+++ b/backend/internal/pkg/geminicli/drive_client.go
@@ -0,0 +1,157 @@
+package geminicli
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"math/rand"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
+)
+
+// DriveStorageInfo represents Google Drive storage quota information
+type DriveStorageInfo struct {
+	Limit int64 `json:"limit"` // Storage limit in bytes
+	Usage int64 `json:"usage"` // Current usage in bytes
+}
+
+// DriveClient interface for Google Drive API operations
+type DriveClient interface {
+	GetStorageQuota(ctx context.Context, accessToken, proxyURL string) (*DriveStorageInfo, error)
+}
+
+type driveClient struct{}
+
+// NewDriveClient creates a new Drive API client
+func NewDriveClient() DriveClient {
+	return &driveClient{}
+}
+
+// GetStorageQuota fetches storage quota from Google Drive API
+func (c *driveClient) GetStorageQuota(ctx context.Context, accessToken, proxyURL string) (*DriveStorageInfo, error) {
+	const driveAPIURL = "https://www.googleapis.com/drive/v3/about?fields=storageQuota"
+
+	req, err := http.NewRequestWithContext(ctx, "GET", driveAPIURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+
+	req.Header.Set("Authorization", "Bearer "+accessToken)
+
+	// Get HTTP client with proxy support
+	client, err := httpclient.GetClient(httpclient.Options{
+		ProxyURL: proxyURL,
+		Timeout:  10 * time.Second,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to create HTTP client: %w", err)
+	}
+
+	sleepWithContext := func(d time.Duration) error {
+		timer := time.NewTimer(d)
+		defer timer.Stop()
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-timer.C:
+			return nil
+		}
+	}
+
+	// Retry logic with exponential backoff (+ jitter) for rate limits and transient failures
+	var resp *http.Response
+	maxRetries := 3
+	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
+	for attempt := 0; attempt < maxRetries; attempt++ {
+		if ctx.Err() != nil {
+			return nil, fmt.Errorf("request cancelled: %w", ctx.Err())
+		}
+
+		resp, err = client.Do(req)
+		if err != nil {
+			// Network error retry
+			if attempt < maxRetries-1 {
+				backoff := time.Duration(1<<uint(attempt)) * time.Second
+				jitter := time.Duration(rng.Intn(1000)) * time.Millisecond
+				if err := sleepWithContext(backoff + jitter); err != nil {
+					return nil, fmt.Errorf("request cancelled: %w", err)
+				}
+				continue
+			}
+			return nil, fmt.Errorf("network error after %d attempts: %w", maxRetries, err)
+		}
+
+		// Success
+		if resp.StatusCode == http.StatusOK {
+			break
+		}
+
+		// Retry 429, 500, 502, 503 with exponential backoff + jitter
+		if (resp.StatusCode == http.StatusTooManyRequests ||
+			resp.StatusCode == http.StatusInternalServerError ||
+			resp.StatusCode == http.StatusBadGateway ||
+			resp.StatusCode == http.StatusServiceUnavailable) && attempt < maxRetries-1 {
+			if err := func() error {
+				defer func() { _ = resp.Body.Close() }()
+				backoff := time.Duration(1<<uint(attempt)) * time.Second
+				jitter := time.Duration(rng.Intn(1000)) * time.Millisecond
+				return sleepWithContext(backoff + jitter)
+			}(); err != nil {
+				return nil, fmt.Errorf("request cancelled: %w", err)
+			}
+			continue
+		}
+
+		break
+	}
+
+	if resp == nil {
+		return nil, fmt.Errorf("request failed: no response received")
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		_ = resp.Body.Close()
+		statusText := http.StatusText(resp.StatusCode)
+		if statusText == "" {
+			statusText = resp.Status
+		}
+		fmt.Printf("[DriveClient] Drive API error: status=%d, msg=%s\n", resp.StatusCode, statusText)
+		// 只返回通用错误
+		return nil, fmt.Errorf("drive API error: status %d", resp.StatusCode)
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	// Parse response
+	var result struct {
+		StorageQuota struct {
+			Limit string `json:"limit"` // Can be string or number
+			Usage string `json:"usage"`
+		} `json:"storageQuota"`
+	}
+
+	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
+		return nil, fmt.Errorf("failed to decode response: %w", err)
+	}
+
+	// Parse limit and usage (handle both string and number formats)
+	var limit, usage int64
+	if result.StorageQuota.Limit != "" {
+		if val, err := strconv.ParseInt(result.StorageQuota.Limit, 10, 64); err == nil {
+			limit = val
+		}
+	}
+	if result.StorageQuota.Usage != "" {
+		if val, err := strconv.ParseInt(result.StorageQuota.Usage, 10, 64); err == nil {
+			usage = val
+		}
+	}
+
+	return &DriveStorageInfo{
+		Limit: limit,
+		Usage: usage,
+	}, nil
+}
diff --git a/backend/internal/pkg/geminicli/drive_client_test.go b/backend/internal/pkg/geminicli/drive_client_test.go
new file mode 100644
index 00000000..b6dd1a69
--- /dev/null
+++ b/backend/internal/pkg/geminicli/drive_client_test.go
@@ -0,0 +1,18 @@
+package geminicli
+
+import "testing"
+
+func TestDriveStorageInfo(t *testing.T) {
+	// 测试 DriveStorageInfo 结构体
+	info := &DriveStorageInfo{
+		Limit: 100 * 1024 * 1024 * 1024, // 100GB
+		Usage: 50 * 1024 * 1024 * 1024,  // 50GB
+	}
+
+	if info.Limit != 100*1024*1024*1024 {
+		t.Errorf("Expected limit 100GB, got %d", info.Limit)
+	}
+	if info.Usage != 50*1024*1024*1024 {
+		t.Errorf("Expected usage 50GB, got %d", info.Usage)
+	}
+}
diff --git a/backend/internal/repository/account_repo.go b/backend/internal/repository/account_repo.go
index 631f4ee4..63bd6abb 100644
--- a/backend/internal/repository/account_repo.go
+++ b/backend/internal/repository/account_repo.go
@@ -124,6 +124,90 @@ func (r *accountRepository) GetByID(ctx context.Context, id int64) (*service.Acc
 	return &accounts[0], nil
 }
 
+func (r *accountRepository) GetByIDs(ctx context.Context, ids []int64) ([]*service.Account, error) {
+	if len(ids) == 0 {
+		return []*service.Account{}, nil
+	}
+
+	// De-duplicate while preserving order of first occurrence.
+	uniqueIDs := make([]int64, 0, len(ids))
+	seen := make(map[int64]struct{}, len(ids))
+	for _, id := range ids {
+		if id <= 0 {
+			continue
+		}
+		if _, ok := seen[id]; ok {
+			continue
+		}
+		seen[id] = struct{}{}
+		uniqueIDs = append(uniqueIDs, id)
+	}
+	if len(uniqueIDs) == 0 {
+		return []*service.Account{}, nil
+	}
+
+	entAccounts, err := r.client.Account.
+		Query().
+		Where(dbaccount.IDIn(uniqueIDs...)).
+		WithProxy().
+		All(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if len(entAccounts) == 0 {
+		return []*service.Account{}, nil
+	}
+
+	accountIDs := make([]int64, 0, len(entAccounts))
+	entByID := make(map[int64]*dbent.Account, len(entAccounts))
+	for _, acc := range entAccounts {
+		entByID[acc.ID] = acc
+		accountIDs = append(accountIDs, acc.ID)
+	}
+
+	groupsByAccount, groupIDsByAccount, accountGroupsByAccount, err := r.loadAccountGroups(ctx, accountIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	outByID := make(map[int64]*service.Account, len(entAccounts))
+	for _, entAcc := range entAccounts {
+		out := accountEntityToService(entAcc)
+		if out == nil {
+			continue
+		}
+
+		// Prefer the preloaded proxy edge when available.
+		if entAcc.Edges.Proxy != nil {
+			out.Proxy = proxyEntityToService(entAcc.Edges.Proxy)
+		}
+
+		if groups, ok := groupsByAccount[entAcc.ID]; ok {
+			out.Groups = groups
+		}
+		if groupIDs, ok := groupIDsByAccount[entAcc.ID]; ok {
+			out.GroupIDs = groupIDs
+		}
+		if ags, ok := accountGroupsByAccount[entAcc.ID]; ok {
+			out.AccountGroups = ags
+		}
+		outByID[entAcc.ID] = out
+	}
+
+	// Preserve input order (first occurrence), and ignore missing IDs.
+	out := make([]*service.Account, 0, len(uniqueIDs))
+	for _, id := range uniqueIDs {
+		if _, ok := entByID[id]; !ok {
+			continue
+		}
+		if acc, ok := outByID[id]; ok && acc != nil {
+			out = append(out, acc)
+		}
+	}
+
+	return out, nil
+}
+
 // ExistsByID 检查指定 ID 的账号是否存在。
 // 相比 GetByID，此方法性能更优，因为：
 //   - 使用 Exist() 方法生成 SELECT EXISTS 查询，只返回布尔值
diff --git a/backend/internal/server/routes/admin.go b/backend/internal/server/routes/admin.go
index 604d14df..04f1285b 100644
--- a/backend/internal/server/routes/admin.go
+++ b/backend/internal/server/routes/admin.go
@@ -110,6 +110,7 @@ func registerAccountRoutes(admin *gin.RouterGroup, h *handler.Handlers) {
 		accounts.DELETE("/:id", h.Admin.Account.Delete)
 		accounts.POST("/:id/test", h.Admin.Account.Test)
 		accounts.POST("/:id/refresh", h.Admin.Account.Refresh)
+		accounts.POST("/:id/refresh-tier", h.Admin.Account.RefreshTier)
 		accounts.GET("/:id/stats", h.Admin.Account.GetStats)
 		accounts.POST("/:id/clear-error", h.Admin.Account.ClearError)
 		accounts.GET("/:id/usage", h.Admin.Account.GetUsage)
@@ -119,6 +120,7 @@ func registerAccountRoutes(admin *gin.RouterGroup, h *handler.Handlers) {
 		accounts.GET("/:id/models", h.Admin.Account.GetAvailableModels)
 		accounts.POST("/batch", h.Admin.Account.BatchCreate)
 		accounts.POST("/batch-update-credentials", h.Admin.Account.BatchUpdateCredentials)
+		accounts.POST("/batch-refresh-tier", h.Admin.Account.BatchRefreshTier)
 		accounts.POST("/bulk-update", h.Admin.Account.BulkUpdate)
 
 		// Claude OAuth routes
diff --git a/backend/internal/service/account_service.go b/backend/internal/service/account_service.go
index 3c5841bd..6a107155 100644
--- a/backend/internal/service/account_service.go
+++ b/backend/internal/service/account_service.go
@@ -17,6 +17,9 @@ var (
 type AccountRepository interface {
 	Create(ctx context.Context, account *Account) error
 	GetByID(ctx context.Context, id int64) (*Account, error)
+	// GetByIDs fetches accounts by IDs in a single query.
+	// It should return all accounts found (missing IDs are ignored).
+	GetByIDs(ctx context.Context, ids []int64) ([]*Account, error)
 	// ExistsByID 检查账号是否存在，仅返回布尔值，用于删除前的轻量级存在性检查
 	ExistsByID(ctx context.Context, id int64) (bool, error)
 	// GetByCRSAccountID finds an account previously synced from CRS.
diff --git a/backend/internal/service/account_service_delete_test.go b/backend/internal/service/account_service_delete_test.go
index 2648b828..43703763 100644
--- a/backend/internal/service/account_service_delete_test.go
+++ b/backend/internal/service/account_service_delete_test.go
@@ -40,6 +40,10 @@ func (s *accountRepoStub) GetByID(ctx context.Context, id int64) (*Account, erro
 	panic("unexpected GetByID call")
 }
 
+func (s *accountRepoStub) GetByIDs(ctx context.Context, ids []int64) ([]*Account, error) {
+	panic("unexpected GetByIDs call")
+}
+
 // ExistsByID 返回预设的存在性检查结果。
 // 这是 Delete 方法调用的第一个仓储方法，用于验证账号是否存在。
 func (s *accountRepoStub) ExistsByID(ctx context.Context, id int64) (bool, error) {
diff --git a/backend/internal/service/admin_service.go b/backend/internal/service/admin_service.go
index feeb19a0..2f0f5f31 100644
--- a/backend/internal/service/admin_service.go
+++ b/backend/internal/service/admin_service.go
@@ -35,6 +35,7 @@ type AdminService interface {
 	// Account management
 	ListAccounts(ctx context.Context, page, pageSize int, platform, accountType, status, search string) ([]Account, int64, error)
 	GetAccount(ctx context.Context, id int64) (*Account, error)
+	GetAccountsByIDs(ctx context.Context, ids []int64) ([]*Account, error)
 	CreateAccount(ctx context.Context, input *CreateAccountInput) (*Account, error)
 	UpdateAccount(ctx context.Context, id int64, input *UpdateAccountInput) (*Account, error)
 	DeleteAccount(ctx context.Context, id int64) error
@@ -611,6 +612,19 @@ func (s *adminServiceImpl) GetAccount(ctx context.Context, id int64) (*Account,
 	return s.accountRepo.GetByID(ctx, id)
 }
 
+func (s *adminServiceImpl) GetAccountsByIDs(ctx context.Context, ids []int64) ([]*Account, error) {
+	if len(ids) == 0 {
+		return []*Account{}, nil
+	}
+
+	accounts, err := s.accountRepo.GetByIDs(ctx, ids)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get accounts by IDs: %w", err)
+	}
+
+	return accounts, nil
+}
+
 func (s *adminServiceImpl) CreateAccount(ctx context.Context, input *CreateAccountInput) (*Account, error) {
 	account := &Account{
 		Name:        input.Name,
diff --git a/backend/internal/service/gateway_multiplatform_test.go b/backend/internal/service/gateway_multiplatform_test.go
index 560c7767..808a48b2 100644
--- a/backend/internal/service/gateway_multiplatform_test.go
+++ b/backend/internal/service/gateway_multiplatform_test.go
@@ -32,6 +32,16 @@ func (m *mockAccountRepoForPlatform) GetByID(ctx context.Context, id int64) (*Ac
 	return nil, errors.New("account not found")
 }
 
+func (m *mockAccountRepoForPlatform) GetByIDs(ctx context.Context, ids []int64) ([]*Account, error) {
+	var result []*Account
+	for _, id := range ids {
+		if acc, ok := m.accountsByID[id]; ok {
+			result = append(result, acc)
+		}
+	}
+	return result, nil
+}
+
 func (m *mockAccountRepoForPlatform) ExistsByID(ctx context.Context, id int64) (bool, error) {
 	if m.accountsByID == nil {
 		return false, nil
diff --git a/backend/internal/service/gemini_multiplatform_test.go b/backend/internal/service/gemini_multiplatform_test.go
index dcc945eb..6ca5052e 100644
--- a/backend/internal/service/gemini_multiplatform_test.go
+++ b/backend/internal/service/gemini_multiplatform_test.go
@@ -25,6 +25,16 @@ func (m *mockAccountRepoForGemini) GetByID(ctx context.Context, id int64) (*Acco
 	return nil, errors.New("account not found")
 }
 
+func (m *mockAccountRepoForGemini) GetByIDs(ctx context.Context, ids []int64) ([]*Account, error) {
+	var result []*Account
+	for _, id := range ids {
+		if acc, ok := m.accountsByID[id]; ok {
+			result = append(result, acc)
+		}
+	}
+	return result, nil
+}
+
 func (m *mockAccountRepoForGemini) ExistsByID(ctx context.Context, id int64) (bool, error) {
 	if m.accountsByID == nil {
 		return false, nil
diff --git a/backend/internal/service/gemini_oauth_service.go b/backend/internal/service/gemini_oauth_service.go
index d1c1c5f6..e9ccae34 100644
--- a/backend/internal/service/gemini_oauth_service.go
+++ b/backend/internal/service/gemini_oauth_service.go
@@ -17,6 +17,26 @@ import (
 	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
 )
 
+const (
+	TierAIPremium          = "AI_PREMIUM"
+	TierGoogleOneStandard  = "GOOGLE_ONE_STANDARD"
+	TierGoogleOneBasic     = "GOOGLE_ONE_BASIC"
+	TierFree               = "FREE"
+	TierGoogleOneUnknown   = "GOOGLE_ONE_UNKNOWN"
+	TierGoogleOneUnlimited = "GOOGLE_ONE_UNLIMITED"
+)
+
+const (
+	GB = 1024 * 1024 * 1024
+	TB = 1024 * GB
+
+	StorageTierUnlimited = 100 * TB // 100TB
+	StorageTierAIPremium = 2 * TB   // 2TB
+	StorageTierStandard  = 200 * GB // 200GB
+	StorageTierBasic     = 100 * GB // 100GB
+	StorageTierFree      = 15 * GB  // 15GB
+)
+
 type GeminiOAuthService struct {
 	sessionStore *geminicli.SessionStore
 	proxyRepo    ProxyRepository
@@ -89,13 +109,14 @@ func (s *GeminiOAuthService) GenerateAuthURL(ctx context.Context, proxyID *int64
 
 	// OAuth client selection:
 	// - code_assist: always use built-in Gemini CLI OAuth client (public), regardless of configured client_id/secret.
+	// - google_one: same as code_assist, uses built-in client for personal Google accounts.
 	// - ai_studio: requires a user-provided OAuth client.
 	oauthCfg := geminicli.OAuthConfig{
 		ClientID:     s.cfg.Gemini.OAuth.ClientID,
 		ClientSecret: s.cfg.Gemini.OAuth.ClientSecret,
 		Scopes:       s.cfg.Gemini.OAuth.Scopes,
 	}
-	if oauthType == "code_assist" {
+	if oauthType == "code_assist" || oauthType == "google_one" {
 		oauthCfg.ClientID = ""
 		oauthCfg.ClientSecret = ""
 	}
@@ -156,15 +177,16 @@ type GeminiExchangeCodeInput struct {
 }
 
 type GeminiTokenInfo struct {
-	AccessToken  string `json:"access_token"`
-	RefreshToken string `json:"refresh_token"`
-	ExpiresIn    int64  `json:"expires_in"`
-	ExpiresAt    int64  `json:"expires_at"`
-	TokenType    string `json:"token_type"`
-	Scope        string `json:"scope,omitempty"`
-	ProjectID    string `json:"project_id,omitempty"`
-	OAuthType    string `json:"oauth_type,omitempty"` // "code_assist" 或 "ai_studio"
-	TierID       string `json:"tier_id,omitempty"`    // Gemini Code Assist tier: LEGACY/PRO/ULTRA
+	AccessToken  string         `json:"access_token"`
+	RefreshToken string         `json:"refresh_token"`
+	ExpiresIn    int64          `json:"expires_in"`
+	ExpiresAt    int64          `json:"expires_at"`
+	TokenType    string         `json:"token_type"`
+	Scope        string         `json:"scope,omitempty"`
+	ProjectID    string         `json:"project_id,omitempty"`
+	OAuthType    string         `json:"oauth_type,omitempty"` // "code_assist" 或 "ai_studio"
+	TierID       string         `json:"tier_id,omitempty"`    // Gemini Code Assist tier: LEGACY/PRO/ULTRA
+	Extra        map[string]any `json:"extra,omitempty"`      // Drive metadata
 }
 
 // validateTierID validates tier_id format and length
@@ -205,6 +227,104 @@ func extractTierIDFromAllowedTiers(allowedTiers []geminicli.AllowedTier) string
 	return tierID
 }
 
+// inferGoogleOneTier infers Google One tier from Drive storage limit
+func inferGoogleOneTier(storageBytes int64) string {
+	if storageBytes <= 0 {
+		return TierGoogleOneUnknown
+	}
+
+	if storageBytes > StorageTierUnlimited {
+		return TierGoogleOneUnlimited
+	}
+	if storageBytes >= StorageTierAIPremium {
+		return TierAIPremium
+	}
+	if storageBytes >= StorageTierStandard {
+		return TierGoogleOneStandard
+	}
+	if storageBytes >= StorageTierBasic {
+		return TierGoogleOneBasic
+	}
+	if storageBytes >= StorageTierFree {
+		return TierFree
+	}
+	return TierGoogleOneUnknown
+}
+
+// fetchGoogleOneTier fetches Google One tier from Drive API
+func (s *GeminiOAuthService) FetchGoogleOneTier(ctx context.Context, accessToken, proxyURL string) (string, *geminicli.DriveStorageInfo, error) {
+	driveClient := geminicli.NewDriveClient()
+
+	storageInfo, err := driveClient.GetStorageQuota(ctx, accessToken, proxyURL)
+	if err != nil {
+		// Check if it's a 403 (scope not granted)
+		if strings.Contains(err.Error(), "status 403") {
+			fmt.Printf("[GeminiOAuth] Drive API scope not available: %v\n", err)
+			return TierGoogleOneUnknown, nil, err
+		}
+		// Other errors
+		fmt.Printf("[GeminiOAuth] Failed to fetch Drive storage: %v\n", err)
+		return TierGoogleOneUnknown, nil, err
+	}
+
+	tierID := inferGoogleOneTier(storageInfo.Limit)
+	return tierID, storageInfo, nil
+}
+
+// RefreshAccountGoogleOneTier 刷新单个账号的 Google One Tier
+func (s *GeminiOAuthService) RefreshAccountGoogleOneTier(
+	ctx context.Context,
+	account *Account,
+) (tierID string, extra map[string]any, credentials map[string]any, err error) {
+	if account == nil {
+		return "", nil, nil, fmt.Errorf("account is nil")
+	}
+
+	// 验证账号类型
+	oauthType, ok := account.Credentials["oauth_type"].(string)
+	if !ok || oauthType != "google_one" {
+		return "", nil, nil, fmt.Errorf("not a google_one OAuth account")
+	}
+
+	// 获取 access_token
+	accessToken, ok := account.Credentials["access_token"].(string)
+	if !ok || accessToken == "" {
+		return "", nil, nil, fmt.Errorf("missing access_token")
+	}
+
+	// 获取 proxy URL
+	var proxyURL string
+	if account.ProxyID != nil && account.Proxy != nil {
+		proxyURL = account.Proxy.URL()
+	}
+
+	// 调用 Drive API
+	tierID, storageInfo, err := s.FetchGoogleOneTier(ctx, accessToken, proxyURL)
+	if err != nil {
+		return "", nil, nil, err
+	}
+
+	// 构建 extra 数据（保留原有 extra 字段）
+	extra = make(map[string]any)
+	for k, v := range account.Extra {
+		extra[k] = v
+	}
+	if storageInfo != nil {
+		extra["drive_storage_limit"] = storageInfo.Limit
+		extra["drive_storage_usage"] = storageInfo.Usage
+		extra["drive_tier_updated_at"] = time.Now().Format(time.RFC3339)
+	}
+
+	// 构建 credentials 数据
+	credentials = make(map[string]any)
+	for k, v := range account.Credentials {
+		credentials[k] = v
+	}
+	credentials["tier_id"] = tierID
+
+	return tierID, extra, credentials, nil
+}
+
 func (s *GeminiOAuthService) ExchangeCode(ctx context.Context, input *GeminiExchangeCodeInput) (*GeminiTokenInfo, error) {
 	session, ok := s.sessionStore.Get(input.SessionID)
 	if !ok {
@@ -272,9 +392,11 @@ func (s *GeminiOAuthService) ExchangeCode(ctx context.Context, input *GeminiExch
 	projectID := sessionProjectID
 	var tierID string
 
-	// 对于 code_assist 模式，project_id 是必需的
+	// 对于 code_assist 模式，project_id 是必需的，需要调用 Code Assist API
+	// 对于 google_one 模式，使用个人 Google 账号，不需要 project_id，配额由 Google 网关自动识别
 	// 对于 ai_studio 模式，project_id 是可选的（不影响使用 AI Studio API）
-	if oauthType == "code_assist" {
+	switch oauthType {
+	case "code_assist":
 		if projectID == "" {
 			var err error
 			projectID, tierID, err = s.fetchProjectID(ctx, tokenResp.AccessToken, proxyURL)
@@ -298,7 +420,37 @@ func (s *GeminiOAuthService) ExchangeCode(ctx context.Context, input *GeminiExch
 		if tierID == "" {
 			tierID = "LEGACY"
 		}
+	case "google_one":
+		// Attempt to fetch Drive storage tier
+		tierID, storageInfo, err := s.FetchGoogleOneTier(ctx, tokenResp.AccessToken, proxyURL)
+		if err != nil {
+			// Log warning but don't block - use fallback
+			fmt.Printf("[GeminiOAuth] Warning: Failed to fetch Drive tier: %v\n", err)
+			tierID = TierGoogleOneUnknown
+		}
+
+		// Store Drive info in extra field for caching
+		if storageInfo != nil {
+			tokenInfo := &GeminiTokenInfo{
+				AccessToken:  tokenResp.AccessToken,
+				RefreshToken: tokenResp.RefreshToken,
+				TokenType:    tokenResp.TokenType,
+				ExpiresIn:    tokenResp.ExpiresIn,
+				ExpiresAt:    expiresAt,
+				Scope:        tokenResp.Scope,
+				ProjectID:    projectID,
+				TierID:       tierID,
+				OAuthType:    oauthType,
+				Extra: map[string]any{
+					"drive_storage_limit":   storageInfo.Limit,
+					"drive_storage_usage":   storageInfo.Usage,
+					"drive_tier_updated_at": time.Now().Format(time.RFC3339),
+				},
+			}
+			return tokenInfo, nil
+		}
 	}
+	// ai_studio 模式不设置 tierID，保持为空
 
 	return &GeminiTokenInfo{
 		AccessToken:  tokenResp.AccessToken,
@@ -427,7 +579,8 @@ func (s *GeminiOAuthService) RefreshAccountToken(ctx context.Context, account *A
 
 	// For Code Assist, project_id is required. Auto-detect if missing.
 	// For AI Studio OAuth, project_id is optional and should not block refresh.
-	if oauthType == "code_assist" {
+	switch oauthType {
+	case "code_assist":
 		// 先设置默认值或保留旧值，确保 tier_id 始终有值
 		if existingTierID != "" {
 			tokenInfo.TierID = existingTierID
@@ -455,6 +608,41 @@ func (s *GeminiOAuthService) RefreshAccountToken(ctx context.Context, account *A
 		if strings.TrimSpace(tokenInfo.ProjectID) == "" {
 			return nil, fmt.Errorf("failed to auto-detect project_id: empty result")
 		}
+	case "google_one":
+		// Check if tier cache is stale (> 24 hours)
+		needsRefresh := true
+		if account.Extra != nil {
+			if updatedAtStr, ok := account.Extra["drive_tier_updated_at"].(string); ok {
+				if updatedAt, err := time.Parse(time.RFC3339, updatedAtStr); err == nil {
+					if time.Since(updatedAt) <= 24*time.Hour {
+						needsRefresh = false
+						// Use cached tier
+						if existingTierID != "" {
+							tokenInfo.TierID = existingTierID
+						}
+					}
+				}
+			}
+		}
+
+		if needsRefresh {
+			tierID, storageInfo, err := s.FetchGoogleOneTier(ctx, tokenInfo.AccessToken, proxyURL)
+			if err == nil && storageInfo != nil {
+				tokenInfo.TierID = tierID
+				tokenInfo.Extra = map[string]any{
+					"drive_storage_limit":   storageInfo.Limit,
+					"drive_storage_usage":   storageInfo.Usage,
+					"drive_tier_updated_at": time.Now().Format(time.RFC3339),
+				}
+			} else {
+				// Fallback to cached or unknown
+				if existingTierID != "" {
+					tokenInfo.TierID = existingTierID
+				} else {
+					tokenInfo.TierID = TierGoogleOneUnknown
+				}
+			}
+		}
 	}
 
 	return tokenInfo, nil
@@ -487,6 +675,12 @@ func (s *GeminiOAuthService) BuildAccountCredentials(tokenInfo *GeminiTokenInfo)
 	if tokenInfo.OAuthType != "" {
 		creds["oauth_type"] = tokenInfo.OAuthType
 	}
+	// Store extra metadata (Drive info) if present
+	if len(tokenInfo.Extra) > 0 {
+		for k, v := range tokenInfo.Extra {
+			creds[k] = v
+		}
+	}
 	return creds
 }
 
diff --git a/backend/internal/service/gemini_oauth_service_test.go b/backend/internal/service/gemini_oauth_service_test.go
new file mode 100644
index 00000000..026e6dc2
--- /dev/null
+++ b/backend/internal/service/gemini_oauth_service_test.go
@@ -0,0 +1,51 @@
+package service
+
+import "testing"
+
+func TestInferGoogleOneTier(t *testing.T) {
+	tests := []struct {
+		name         string
+		storageBytes int64
+		expectedTier string
+	}{
+		{"Negative storage", -1, TierGoogleOneUnknown},
+		{"Zero storage", 0, TierGoogleOneUnknown},
+
+		// Free tier boundary (15GB)
+		{"Below free tier", 10 * GB, TierGoogleOneUnknown},
+		{"Just below free tier", StorageTierFree - 1, TierGoogleOneUnknown},
+		{"Free tier (15GB)", StorageTierFree, TierFree},
+
+		// Basic tier boundary (100GB)
+		{"Between free and basic", 50 * GB, TierFree},
+		{"Just below basic tier", StorageTierBasic - 1, TierFree},
+		{"Basic tier (100GB)", StorageTierBasic, TierGoogleOneBasic},
+
+		// Standard tier boundary (200GB)
+		{"Between basic and standard", 150 * GB, TierGoogleOneBasic},
+		{"Just below standard tier", StorageTierStandard - 1, TierGoogleOneBasic},
+		{"Standard tier (200GB)", StorageTierStandard, TierGoogleOneStandard},
+
+		// AI Premium tier boundary (2TB)
+		{"Between standard and premium", 1 * TB, TierGoogleOneStandard},
+		{"Just below AI Premium tier", StorageTierAIPremium - 1, TierGoogleOneStandard},
+		{"AI Premium tier (2TB)", StorageTierAIPremium, TierAIPremium},
+
+		// Unlimited tier boundary (> 100TB)
+		{"Between premium and unlimited", 50 * TB, TierAIPremium},
+		{"At unlimited threshold (100TB)", StorageTierUnlimited, TierAIPremium},
+		{"Unlimited tier (100TB+)", StorageTierUnlimited + 1, TierGoogleOneUnlimited},
+		{"Unlimited tier (101TB+)", 101 * TB, TierGoogleOneUnlimited},
+		{"Very large storage", 1000 * TB, TierGoogleOneUnlimited},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := inferGoogleOneTier(tt.storageBytes)
+			if result != tt.expectedTier {
+				t.Errorf("inferGoogleOneTier(%d) = %s, want %s",
+					tt.storageBytes, result, tt.expectedTier)
+			}
+		})
+	}
+}
diff --git a/backend/internal/service/ratelimit_service.go b/backend/internal/service/ratelimit_service.go
index 0511d950..57d606fb 100644
--- a/backend/internal/service/ratelimit_service.go
+++ b/backend/internal/service/ratelimit_service.go
@@ -18,7 +18,7 @@ type RateLimitService struct {
 	usageRepo          UsageLogRepository
 	cfg                *config.Config
 	geminiQuotaService *GeminiQuotaService
-	usageCacheMu       sync.Mutex
+	usageCacheMu       sync.RWMutex
 	usageCache         map[int64]*geminiUsageCacheEntry
 }
 
@@ -138,8 +138,8 @@ func (s *RateLimitService) PreCheckUsage(ctx context.Context, account *Account,
 }
 
 func (s *RateLimitService) getGeminiUsageTotals(accountID int64, windowStart, now time.Time) (GeminiUsageTotals, bool) {
-	s.usageCacheMu.Lock()
-	defer s.usageCacheMu.Unlock()
+	s.usageCacheMu.RLock()
+	defer s.usageCacheMu.RUnlock()
 
 	if s.usageCache == nil {
 		return GeminiUsageTotals{}, false
diff --git a/backend/migrations/017_add_gemini_tier_id.sql b/backend/migrations/024_add_gemini_tier_id.sql
similarity index 94%
rename from backend/migrations/017_add_gemini_tier_id.sql
rename to backend/migrations/024_add_gemini_tier_id.sql
index 0388a412..d9ac7afe 100644
--- a/backend/migrations/017_add_gemini_tier_id.sql
+++ b/backend/migrations/024_add_gemini_tier_id.sql
@@ -26,5 +26,5 @@ UPDATE accounts
 SET credentials = credentials - 'tier_id'
 WHERE platform = 'gemini'
   AND type = 'oauth'
-  AND credentials->>'oauth_type' = 'code_assist';
+  AND credentials ? 'tier_id';
 -- +goose StatementEnd
diff --git a/frontend/src/components/account/AccountQuotaInfo.vue b/frontend/src/components/account/AccountQuotaInfo.vue
index c20d685d..512b4451 100644
--- a/frontend/src/components/account/AccountQuotaInfo.vue
+++ b/frontend/src/components/account/AccountQuotaInfo.vue
@@ -48,6 +48,12 @@ const isCodeAssist = computed(() => {
   return creds?.oauth_type === 'code_assist' || (!creds?.oauth_type && !!creds?.project_id)
 })
 
+// 是否为 Google One OAuth
+const isGoogleOne = computed(() => {
+  const creds = props.account.credentials as GeminiCredentials | undefined
+  return creds?.oauth_type === 'google_one'
+})
+
 // 是否应该显示配额信息
 const shouldShowQuota = computed(() => {
   return props.account.platform === 'gemini'
@@ -55,33 +61,73 @@ const shouldShowQuota = computed(() => {
 
 // Tier 标签文本
 const tierLabel = computed(() => {
+  const creds = props.account.credentials as GeminiCredentials | undefined
+
   if (isCodeAssist.value) {
-    const creds = props.account.credentials as GeminiCredentials | undefined
+    // GCP Code Assist: 显示 GCP tier
     const tierMap: Record<string, string> = {
       LEGACY: 'Free',
       PRO: 'Pro',
-      ULTRA: 'Ultra'
+      ULTRA: 'Ultra',
+      'standard-tier': 'Standard',
+      'pro-tier': 'Pro',
+      'ultra-tier': 'Ultra'
     }
-    return tierMap[creds?.tier_id || ''] || 'Unknown'
+    return tierMap[creds?.tier_id || ''] || (creds?.tier_id ? 'GCP' : 'Unknown')
   }
+
+  if (isGoogleOne.value) {
+    // Google One: tier 映射
+    const tierMap: Record<string, string> = {
+      AI_PREMIUM: 'AI Premium',
+      GOOGLE_ONE_STANDARD: 'Standard',
+      GOOGLE_ONE_BASIC: 'Basic',
+      FREE: 'Free',
+      GOOGLE_ONE_UNKNOWN: 'Personal',
+      GOOGLE_ONE_UNLIMITED: 'Unlimited'
+    }
+    return tierMap[creds?.tier_id || ''] || 'Personal'
+  }
+
+  // AI Studio 或其他
   return 'Gemini'
 })
 
 // Tier Badge 样式
 const tierBadgeClass = computed(() => {
-  if (!isCodeAssist.value) {
-    return 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-400'
-  }
   const creds = props.account.credentials as GeminiCredentials | undefined
-  const tierColorMap: Record<string, string> = {
-    LEGACY: 'bg-gray-100 text-gray-700 dark:bg-gray-900/30 dark:text-gray-400',
-    PRO: 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-400',
-    ULTRA: 'bg-amber-100 text-amber-700 dark:bg-amber-900/30 dark:text-amber-400'
+
+  if (isCodeAssist.value) {
+    // GCP Code Assist 样式
+    const tierColorMap: Record<string, string> = {
+      LEGACY: 'bg-gray-100 text-gray-700 dark:bg-gray-900/30 dark:text-gray-400',
+      PRO: 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-400',
+      ULTRA: 'bg-amber-100 text-amber-700 dark:bg-amber-900/30 dark:text-amber-400',
+      'standard-tier': 'bg-green-100 text-green-700 dark:bg-green-900/30 dark:text-green-400',
+      'pro-tier': 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-400',
+      'ultra-tier': 'bg-amber-100 text-amber-700 dark:bg-amber-900/30 dark:text-amber-400'
+    }
+    return (
+      tierColorMap[creds?.tier_id || ''] ||
+      'bg-gray-100 text-gray-700 dark:bg-gray-900/30 dark:text-gray-400'
+    )
   }
-  return (
-    tierColorMap[creds?.tier_id || ''] ||
-    'bg-gray-100 text-gray-700 dark:bg-gray-900/30 dark:text-gray-400'
-  )
+
+  if (isGoogleOne.value) {
+    // Google One tier 样式
+    const tierColorMap: Record<string, string> = {
+      AI_PREMIUM: 'bg-purple-100 text-purple-700 dark:bg-purple-900/30 dark:text-purple-400',
+      GOOGLE_ONE_STANDARD: 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-400',
+      GOOGLE_ONE_BASIC: 'bg-green-100 text-green-700 dark:bg-green-900/30 dark:text-green-400',
+      FREE: 'bg-gray-100 text-gray-700 dark:bg-gray-900/30 dark:text-gray-400',
+      GOOGLE_ONE_UNKNOWN: 'bg-gray-100 text-gray-700 dark:bg-gray-900/30 dark:text-gray-400',
+      GOOGLE_ONE_UNLIMITED: 'bg-amber-100 text-amber-700 dark:bg-amber-900/30 dark:text-amber-400'
+    }
+    return tierColorMap[creds?.tier_id || ''] || 'bg-purple-100 text-purple-700 dark:bg-purple-900/30 dark:text-purple-400'
+  }
+
+  // AI Studio 默认样式：蓝色
+  return 'bg-blue-100 text-blue-700 dark:bg-blue-900/30 dark:text-blue-400'
 })
 
 // 是否限流
diff --git a/frontend/src/components/account/AccountUsageCell.vue b/frontend/src/components/account/AccountUsageCell.vue
index e743c1d2..8dfb9f38 100644
--- a/frontend/src/components/account/AccountUsageCell.vue
+++ b/frontend/src/components/account/AccountUsageCell.vue
@@ -568,6 +568,24 @@ const isGeminiCodeAssist = computed(() => {
 // Gemini 账户类型显示标签
 const geminiTierLabel = computed(() => {
   if (!geminiTier.value) return null
+
+  const creds = props.account.credentials as GeminiCredentials | undefined
+  const isGoogleOne = creds?.oauth_type === 'google_one'
+
+  if (isGoogleOne) {
+    // Google One tier 标签
+    const tierMap: Record<string, string> = {
+      AI_PREMIUM: t('admin.accounts.tier.aiPremium'),
+      GOOGLE_ONE_STANDARD: t('admin.accounts.tier.standard'),
+      GOOGLE_ONE_BASIC: t('admin.accounts.tier.basic'),
+      FREE: t('admin.accounts.tier.free'),
+      GOOGLE_ONE_UNKNOWN: t('admin.accounts.tier.personal'),
+      GOOGLE_ONE_UNLIMITED: t('admin.accounts.tier.unlimited')
+    }
+    return tierMap[geminiTier.value] || t('admin.accounts.tier.personal')
+  }
+
+  // Code Assist tier 标签
   const tierMap: Record<string, string> = {
     LEGACY: t('admin.accounts.tier.free'),
     PRO: t('admin.accounts.tier.pro'),
@@ -578,6 +596,25 @@ const geminiTierLabel = computed(() => {
 
 // Gemini 账户类型徽章样式
 const geminiTierClass = computed(() => {
+  if (!geminiTier.value) return ''
+
+  const creds = props.account.credentials as GeminiCredentials | undefined
+  const isGoogleOne = creds?.oauth_type === 'google_one'
+
+  if (isGoogleOne) {
+    // Google One tier 颜色
+    const colorMap: Record<string, string> = {
+      AI_PREMIUM: 'bg-purple-100 text-purple-600 dark:bg-purple-900/40 dark:text-purple-300',
+      GOOGLE_ONE_STANDARD: 'bg-blue-100 text-blue-600 dark:bg-blue-900/40 dark:text-blue-300',
+      GOOGLE_ONE_BASIC: 'bg-green-100 text-green-600 dark:bg-green-900/40 dark:text-green-300',
+      FREE: 'bg-gray-100 text-gray-600 dark:bg-gray-700 dark:text-gray-300',
+      GOOGLE_ONE_UNKNOWN: 'bg-gray-100 text-gray-600 dark:bg-gray-700 dark:text-gray-300',
+      GOOGLE_ONE_UNLIMITED: 'bg-amber-100 text-amber-600 dark:bg-amber-900/40 dark:text-amber-300'
+    }
+    return colorMap[geminiTier.value] || 'bg-gray-100 text-gray-600 dark:bg-gray-700 dark:text-gray-300'
+  }
+
+  // Code Assist tier 颜色
   switch (geminiTier.value) {
     case 'LEGACY':
       return 'bg-gray-100 text-gray-600 dark:bg-gray-700 dark:text-gray-300'
diff --git a/frontend/src/components/account/CreateAccountModal.vue b/frontend/src/components/account/CreateAccountModal.vue
index 7cb54dc0..0f188e08 100644
--- a/frontend/src/components/account/CreateAccountModal.vue
+++ b/frontend/src/components/account/CreateAccountModal.vue
@@ -455,6 +455,52 @@
         <div v-if="accountCategory === 'oauth-based'" class="mt-4">
           <label class="input-label">{{ t('admin.accounts.oauth.gemini.oauthTypeLabel') }}</label>
           <div class="mt-2 grid grid-cols-2 gap-3">
+            <!-- Google One OAuth -->
+            <button
+              type="button"
+              @click="handleSelectGeminiOAuthType('google_one')"
+              :class="[
+                'flex items-center gap-3 rounded-lg border-2 p-3 text-left transition-all',
+                geminiOAuthType === 'google_one'
+                  ? 'border-purple-500 bg-purple-50 dark:bg-purple-900/20'
+                  : 'border-gray-200 hover:border-purple-300 dark:border-dark-600 dark:hover:border-purple-700'
+              ]"
+            >
+              <div
+                :class="[
+                  'flex h-8 w-8 items-center justify-center rounded-lg',
+                  geminiOAuthType === 'google_one'
+                    ? 'bg-purple-500 text-white'
+                    : 'bg-gray-100 text-gray-500 dark:bg-dark-600 dark:text-gray-400'
+                ]"
+              >
+                <svg class="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="1.5">
+                  <path stroke-linecap="round" stroke-linejoin="round" d="M15.75 6a3.75 3.75 0 11-7.5 0 3.75 3.75 0 017.5 0zM4.501 20.118a7.5 7.5 0 0114.998 0A17.933 17.933 0 0112 21.75c-2.676 0-5.216-.584-7.499-1.632z" />
+                </svg>
+              </div>
+              <div class="min-w-0">
+                <span class="block text-sm font-medium text-gray-900 dark:text-white">
+                  Google One
+                </span>
+                <span class="text-xs text-gray-500 dark:text-gray-400">
+                  个人账号，享受 Google One 订阅配额
+                </span>
+                <div class="mt-2 flex flex-wrap gap-1">
+                  <span
+                    class="rounded bg-purple-100 px-2 py-0.5 text-[10px] font-semibold text-purple-700 dark:bg-purple-900/40 dark:text-purple-300"
+                  >
+                    推荐个人用户
+                  </span>
+                  <span
+                    class="rounded bg-emerald-100 px-2 py-0.5 text-[10px] font-semibold text-emerald-700 dark:bg-emerald-900/40 dark:text-emerald-300"
+                  >
+                    无需 GCP
+                  </span>
+                </div>
+              </div>
+            </button>
+
+            <!-- GCP Code Assist OAuth -->
             <button
               type="button"
               @click="handleSelectGeminiOAuthType('code_assist')"
@@ -479,13 +525,13 @@
               </div>
               <div class="min-w-0">
                 <span class="block text-sm font-medium text-gray-900 dark:text-white">
-                  {{ t('admin.accounts.gemini.oauthType.builtInTitle') }}
+                  GCP Code Assist
                 </span>
                 <span class="text-xs text-gray-500 dark:text-gray-400">
-                  {{ t('admin.accounts.gemini.oauthType.builtInDesc') }}
+                  企业级，需要 GCP 项目
                 </span>
                 <div class="mt-1 text-xs text-gray-500 dark:text-gray-400">
-                  {{ t('admin.accounts.gemini.oauthType.builtInRequirement') }}
+                  需要激活 GCP 项目并绑定信用卡
                   <a
                     :href="geminiHelpLinks.gcpProject"
                     class="ml-1 text-blue-600 hover:underline dark:text-blue-400"
@@ -499,94 +545,110 @@
                   <span
                     class="rounded bg-blue-100 px-2 py-0.5 text-[10px] font-semibold text-blue-700 dark:bg-blue-900/40 dark:text-blue-300"
                   >
-                    {{ t('admin.accounts.gemini.oauthType.badges.recommended') }}
+                    企业用户
                   </span>
                   <span
                     class="rounded bg-emerald-100 px-2 py-0.5 text-[10px] font-semibold text-emerald-700 dark:bg-emerald-900/40 dark:text-emerald-300"
                   >
-                    {{ t('admin.accounts.gemini.oauthType.badges.highConcurrency') }}
-                  </span>
-                  <span
-                    class="rounded bg-gray-100 px-2 py-0.5 text-[10px] font-semibold text-gray-700 dark:bg-gray-800 dark:text-gray-300"
-                  >
-                    {{ t('admin.accounts.gemini.oauthType.badges.noAdmin') }}
+                    高并发
                   </span>
                 </div>
               </div>
             </button>
+          </div>
 
-            <div class="group relative">
-              <button
-                type="button"
-                :disabled="!geminiAIStudioOAuthEnabled"
-                @click="handleSelectGeminiOAuthType('ai_studio')"
+          <!-- Advanced Options Toggle -->
+          <div class="mt-3">
+            <button
+              type="button"
+              @click="showAdvancedOAuth = !showAdvancedOAuth"
+              class="flex items-center gap-2 text-sm text-gray-600 hover:text-gray-900 dark:text-gray-400 dark:hover:text-gray-200"
+            >
+              <svg
+                :class="['h-4 w-4 transition-transform', showAdvancedOAuth ? 'rotate-90' : '']"
+                fill="none"
+                viewBox="0 0 24 24"
+                stroke="currentColor"
+                stroke-width="2"
+              >
+                <path stroke-linecap="round" stroke-linejoin="round" d="M9 5l7 7-7 7" />
+              </svg>
+              <span>{{ showAdvancedOAuth ? '隐藏' : '显示' }}高级选项（自建 OAuth Client）</span>
+            </button>
+          </div>
+
+          <!-- Custom OAuth Client (Advanced) -->
+          <div v-if="showAdvancedOAuth" class="mt-3 group relative">
+            <button
+              type="button"
+              :disabled="!geminiAIStudioOAuthEnabled"
+              @click="handleSelectGeminiOAuthType('ai_studio')"
+              :class="[
+                'flex w-full items-center gap-3 rounded-lg border-2 p-3 text-left transition-all',
+                !geminiAIStudioOAuthEnabled ? 'cursor-not-allowed opacity-60' : '',
+                geminiOAuthType === 'ai_studio'
+                  ? 'border-amber-500 bg-amber-50 dark:bg-amber-900/20'
+                  : 'border-gray-200 hover:border-amber-300 dark:border-dark-600 dark:hover:border-amber-700'
+              ]"
+            >
+              <div
                 :class="[
-                  'flex w-full items-center gap-3 rounded-lg border-2 p-3 text-left transition-all',
-                  !geminiAIStudioOAuthEnabled ? 'cursor-not-allowed opacity-60' : '',
+                  'flex h-8 w-8 items-center justify-center rounded-lg',
                   geminiOAuthType === 'ai_studio'
-                    ? 'border-purple-500 bg-purple-50 dark:bg-purple-900/20'
-                    : 'border-gray-200 hover:border-purple-300 dark:border-dark-600 dark:hover:border-purple-700'
+                    ? 'bg-amber-500 text-white'
+                    : 'bg-gray-100 text-gray-500 dark:bg-dark-600 dark:text-gray-400'
                 ]"
               >
-                <div
-                  :class="[
-                    'flex h-8 w-8 items-center justify-center rounded-lg',
-                    geminiOAuthType === 'ai_studio'
-                      ? 'bg-purple-500 text-white'
-                      : 'bg-gray-100 text-gray-500 dark:bg-dark-600 dark:text-gray-400'
-                  ]"
+                <svg
+                  class="h-4 w-4"
+                  fill="none"
+                  viewBox="0 0 24 24"
+                  stroke="currentColor"
+                  stroke-width="1.5"
                 >
-                  <svg
-                    class="h-4 w-4"
-                    fill="none"
-                    viewBox="0 0 24 24"
-                    stroke="currentColor"
-                    stroke-width="1.5"
-                  >
-                    <path
-                      stroke-linecap="round"
-                      stroke-linejoin="round"
-                      d="M9.813 15.904L9 18.75l-.813-2.846a4.5 4.5 0 00-3.09-3.09L2.25 12l2.846-.813a4.5 4.5 0 003.09-3.09L9 5.25l.813 2.846a4.5 4.5 0 003.09 3.09L15.75 12l-2.846.813a4.5 4.5 0 00-3.09 3.09z"
-                    />
-                  </svg>
-                </div>
-                <div class="min-w-0">
-                  <span class="block text-sm font-medium text-gray-900 dark:text-white">
-                    {{ t('admin.accounts.gemini.oauthType.customTitle') }}
-                  </span>
-                  <span class="text-xs text-gray-500 dark:text-gray-400">
-                    {{ t('admin.accounts.gemini.oauthType.customDesc') }}
-                  </span>
-                  <div class="mt-1 text-xs text-gray-500 dark:text-gray-400">
-                    {{ t('admin.accounts.gemini.oauthType.customRequirement') }}
-                  </div>
-                  <div class="mt-2 flex flex-wrap gap-1">
-                    <span
-                      class="rounded bg-purple-100 px-2 py-0.5 text-[10px] font-semibold text-purple-700 dark:bg-purple-900/40 dark:text-purple-300"
-                    >
-                      {{ t('admin.accounts.gemini.oauthType.badges.orgManaged') }}
-                    </span>
-                    <span
-                      class="rounded bg-amber-100 px-2 py-0.5 text-[10px] font-semibold text-amber-700 dark:bg-amber-900/40 dark:text-amber-300"
-                    >
-                      {{ t('admin.accounts.gemini.oauthType.badges.adminRequired') }}
-                    </span>
-                  </div>
-                </div>
-                <span
-                  v-if="!geminiAIStudioOAuthEnabled"
-                  class="ml-auto shrink-0 rounded bg-amber-100 px-2 py-0.5 text-xs text-amber-700 dark:bg-amber-900/30 dark:text-amber-300"
-                >
-                  {{ t('admin.accounts.oauth.gemini.aiStudioNotConfiguredShort') }}
-                </span>
-              </button>
-
-              <div
-                v-if="!geminiAIStudioOAuthEnabled"
-                class="pointer-events-none absolute right-0 top-full z-50 mt-2 w-80 rounded-md border border-amber-200 bg-amber-50 px-3 py-2 text-xs text-amber-800 opacity-0 shadow-lg transition-opacity group-hover:opacity-100 dark:border-amber-700 dark:bg-amber-900/40 dark:text-amber-200"
-              >
-                {{ t('admin.accounts.oauth.gemini.aiStudioNotConfiguredTip') }}
+                  <path
+                    stroke-linecap="round"
+                    stroke-linejoin="round"
+                    d="M9.813 15.904L9 18.75l-.813-2.846a4.5 4.5 0 00-3.09-3.09L2.25 12l2.846-.813a4.5 4.5 0 003.09-3.09L9 5.25l.813 2.846a4.5 4.5 0 003.09 3.09L15.75 12l-2.846.813a4.5 4.5 0 00-3.09 3.09z"
+                  />
+                </svg>
               </div>
+              <div class="min-w-0">
+                <span class="block text-sm font-medium text-gray-900 dark:text-white">
+                  {{ t('admin.accounts.gemini.oauthType.customTitle') }}
+                </span>
+                <span class="text-xs text-gray-500 dark:text-gray-400">
+                  {{ t('admin.accounts.gemini.oauthType.customDesc') }}
+                </span>
+                <div class="mt-1 text-xs text-gray-500 dark:text-gray-400">
+                  {{ t('admin.accounts.gemini.oauthType.customRequirement') }}
+                </div>
+                <div class="mt-2 flex flex-wrap gap-1">
+                  <span
+                    class="rounded bg-amber-100 px-2 py-0.5 text-[10px] font-semibold text-amber-700 dark:bg-amber-900/40 dark:text-amber-300"
+                  >
+                    {{ t('admin.accounts.gemini.oauthType.badges.orgManaged') }}
+                  </span>
+                  <span
+                    class="rounded bg-amber-100 px-2 py-0.5 text-[10px] font-semibold text-amber-700 dark:bg-amber-900/40 dark:text-amber-300"
+                  >
+                    {{ t('admin.accounts.gemini.oauthType.badges.adminRequired') }}
+                  </span>
+                </div>
+              </div>
+              <span
+                v-if="!geminiAIStudioOAuthEnabled"
+                class="ml-auto shrink-0 rounded bg-amber-100 px-2 py-0.5 text-xs text-amber-700 dark:bg-amber-900/30 dark:text-amber-300"
+              >
+                {{ t('admin.accounts.oauth.gemini.aiStudioNotConfiguredShort') }}
+              </span>
+            </button>
+
+            <div
+              v-if="!geminiAIStudioOAuthEnabled"
+              class="pointer-events-none absolute right-0 top-full z-50 mt-2 w-80 rounded-md border border-amber-200 bg-amber-50 px-3 py-2 text-xs text-amber-800 opacity-0 shadow-lg transition-opacity group-hover:opacity-100 dark:border-amber-700 dark:bg-amber-900/40 dark:text-amber-200"
+            >
+              {{ t('admin.accounts.oauth.gemini.aiStudioNotConfiguredTip') }}
             </div>
           </div>
         </div>
@@ -1610,8 +1672,9 @@ const selectedErrorCodes = ref<number[]>([])
 const customErrorCodeInput = ref<number | null>(null)
 const interceptWarmupRequests = ref(false)
 const mixedScheduling = ref(false) // For antigravity accounts: enable mixed scheduling
-const geminiOAuthType = ref<'code_assist' | 'ai_studio'>('code_assist')
+const geminiOAuthType = ref<'code_assist' | 'google_one' | 'ai_studio'>('google_one')
 const geminiAIStudioOAuthEnabled = ref(false)
+const showAdvancedOAuth = ref(false)
 
 // Common models for whitelist - Anthropic
 const anthropicModels = [
@@ -1902,7 +1965,7 @@ watch(
   { immediate: true }
 )
 
-const handleSelectGeminiOAuthType = (oauthType: 'code_assist' | 'ai_studio') => {
+const handleSelectGeminiOAuthType = (oauthType: 'code_assist' | 'google_one' | 'ai_studio') => {
   if (oauthType === 'ai_studio' && !geminiAIStudioOAuthEnabled.value) {
     appStore.showError(t('admin.accounts.oauth.gemini.aiStudioNotConfigured'))
     return
diff --git a/frontend/src/composables/useGeminiOAuth.ts b/frontend/src/composables/useGeminiOAuth.ts
index fb20cc2f..14920417 100644
--- a/frontend/src/composables/useGeminiOAuth.ts
+++ b/frontend/src/composables/useGeminiOAuth.ts
@@ -93,7 +93,13 @@ export function useGeminiOAuth() {
       const tokenInfo = await adminAPI.gemini.exchangeCode(payload as any)
       return tokenInfo as GeminiTokenInfo
     } catch (err: any) {
-      error.value = err.response?.data?.detail || t('admin.accounts.oauth.gemini.failedToExchangeCode')
+      // Check for specific missing project_id error
+      const errorMessage = err.message || err.response?.data?.message || ''
+      if (errorMessage.includes('missing project_id')) {
+        error.value = t('admin.accounts.oauth.gemini.missingProjectId')
+      } else {
+        error.value = errorMessage || t('admin.accounts.oauth.gemini.failedToExchangeCode')
+      }
       appStore.showError(error.value)
       return null
     } finally {
diff --git a/frontend/src/i18n/locales/en.ts b/frontend/src/i18n/locales/en.ts
index ac958590..33789586 100644
--- a/frontend/src/i18n/locales/en.ts
+++ b/frontend/src/i18n/locales/en.ts
@@ -1076,6 +1076,7 @@ export default {
 	          failedToGenerateUrl: 'Failed to generate Gemini auth URL',
 	          missingExchangeParams: 'Missing auth code, session ID, or state',
 	          failedToExchangeCode: 'Failed to exchange Gemini auth code',
+	          missingProjectId: 'GCP Project ID retrieval failed: Your Google account is not linked to an active GCP project. Please activate GCP and bind a credit card in Google Cloud Console, or manually enter the Project ID during authorization.',
 	          modelPassthrough: 'Gemini Model Passthrough',
 	          modelPassthroughDesc:
 	            'All model requests are forwarded directly to the Gemini API without model restrictions or mappings.',
@@ -1290,7 +1291,12 @@ export default {
       tier: {
         free: 'Free',
         pro: 'Pro',
-        ultra: 'Ultra'
+        ultra: 'Ultra',
+        aiPremium: 'AI Premium',
+        standard: 'Standard',
+        basic: 'Basic',
+        personal: 'Personal',
+        unlimited: 'Unlimited'
       },
       ineligibleWarning:
         'This account is not eligible for Antigravity, but API forwarding still works. Use at your own risk.'
diff --git a/frontend/src/i18n/locales/zh.ts b/frontend/src/i18n/locales/zh.ts
index b4de5ada..45d1a9a8 100644
--- a/frontend/src/i18n/locales/zh.ts
+++ b/frontend/src/i18n/locales/zh.ts
@@ -996,7 +996,12 @@ export default {
       tier: {
         free: 'Free',
         pro: 'Pro',
-        ultra: 'Ultra'
+        ultra: 'Ultra',
+        aiPremium: 'AI Premium',
+        standard: '标准版',
+        basic: '基础版',
+        personal: '个人版',
+        unlimited: '无限制'
       },
       ineligibleWarning:
         '该账号无 Antigravity 使用权限，但仍能进行 API 转发。继续使用请自行承担风险。',
@@ -1215,6 +1220,7 @@ export default {
 	          failedToGenerateUrl: '生成 Gemini 授权链接失败',
 	          missingExchangeParams: '缺少 code / session_id / state',
 	          failedToExchangeCode: 'Gemini 授权码兑换失败',
+	          missingProjectId: 'GCP Project ID 获取失败：您的 Google 账号未关联有效的 GCP 项目。请前往 Google Cloud Console 激活 GCP 并绑定信用卡，或在授权时手动填写 Project ID。',
 	          modelPassthrough: 'Gemini 直接转发模型',
 	          modelPassthroughDesc: '所有模型请求将直接转发至 Gemini API，不进行模型限制或映射。',
 	          stateWarningTitle: '提示',