diff --git a/backend/internal/handler/admin/account_handler.go b/backend/internal/handler/admin/account_handler.go
index 33c91dae..c81bcc29 100644
--- a/backend/internal/handler/admin/account_handler.go
+++ b/backend/internal/handler/admin/account_handler.go
@@ -211,12 +211,8 @@ func (h *AccountHandler) List(c *gin.Context) {
 			}
 			accCopy := acc // 闭包捕获
 			g.Go(func() error {
-				var startTime time.Time
-				if accCopy.SessionWindowStart != nil {
-					startTime = *accCopy.SessionWindowStart
-				} else {
-					startTime = time.Now().Add(-5 * time.Hour)
-				}
+				// 使用统一的窗口开始时间计算逻辑（考虑窗口过期情况）
+				startTime := accCopy.GetCurrentWindowStartTime()
 				stats, err := h.accountUsageService.GetAccountWindowStats(gctx, accCopy.ID, startTime)
 				if err == nil && stats != nil {
 					mu.Lock()
diff --git a/backend/internal/repository/account_repo.go b/backend/internal/repository/account_repo.go
index f7725820..6f4f0e81 100644
--- a/backend/internal/repository/account_repo.go
+++ b/backend/internal/repository/account_repo.go
@@ -960,7 +960,16 @@ func (r *accountRepository) UpdateSessionWindow(ctx context.Context, id int64, s
 		builder.SetSessionWindowEnd(*end)
 	}
 	_, err := builder.Save(ctx)
-	return err
+	if err != nil {
+		return err
+	}
+	// 触发调度器缓存更新（仅当窗口时间有变化时）
+	if start != nil || end != nil {
+		if err := enqueueSchedulerOutbox(ctx, r.sql, service.SchedulerOutboxEventAccountChanged, &id, nil, nil); err != nil {
+			log.Printf("[SchedulerOutbox] enqueue session window update failed: account=%d err=%v", id, err)
+		}
+	}
+	return nil
 }
 
 func (r *accountRepository) SetSchedulable(ctx context.Context, id int64, schedulable bool) error {
diff --git a/backend/internal/service/account.go b/backend/internal/service/account.go
index 16c6bb45..94fa107e 100644
--- a/backend/internal/service/account.go
+++ b/backend/internal/service/account.go
@@ -671,6 +671,23 @@ func (a *Account) CheckWindowCostSchedulability(currentWindowCost float64) Windo
 	return WindowCostNotSchedulable
 }
 
+// GetCurrentWindowStartTime 获取当前有效的窗口开始时间
+// 逻辑：
+// 1. 如果窗口未过期（SessionWindowEnd 存在且在当前时间之后），使用记录的 SessionWindowStart
+// 2. 否则（窗口过期或未设置），使用新的预测窗口开始时间（从当前整点开始）
+func (a *Account) GetCurrentWindowStartTime() time.Time {
+	now := time.Now()
+
+	// 窗口未过期，使用记录的窗口开始时间
+	if a.SessionWindowStart != nil && a.SessionWindowEnd != nil && now.Before(*a.SessionWindowEnd) {
+		return *a.SessionWindowStart
+	}
+
+	// 窗口已过期或未设置，预测新的窗口开始时间（从当前整点开始）
+	// 与 ratelimit_service.go 中 UpdateSessionWindow 的预测逻辑保持一致
+	return time.Date(now.Year(), now.Month(), now.Day(), now.Hour(), 0, 0, 0, now.Location())
+}
+
 // parseExtraFloat64 从 extra 字段解析 float64 值
 func parseExtraFloat64(value any) float64 {
 	switch v := value.(type) {
diff --git a/backend/internal/service/account_usage_service.go b/backend/internal/service/account_usage_service.go
index 6f012385..93d8a2f3 100644
--- a/backend/internal/service/account_usage_service.go
+++ b/backend/internal/service/account_usage_service.go
@@ -369,12 +369,8 @@ func (s *AccountUsageService) addWindowStats(ctx context.Context, account *Accou
 
 	// 如果没有缓存，从数据库查询
 	if windowStats == nil {
-		var startTime time.Time
-		if account.SessionWindowStart != nil {
-			startTime = *account.SessionWindowStart
-		} else {
-			startTime = time.Now().Add(-5 * time.Hour)
-		}
+		// 使用统一的窗口开始时间计算逻辑（考虑窗口过期情况）
+		startTime := account.GetCurrentWindowStartTime()
 
 		stats, err := s.usageLogRepo.GetAccountWindowStats(ctx, account.ID, startTime)
 		if err != nil {
diff --git a/backend/internal/service/gateway_service.go b/backend/internal/service/gateway_service.go
index 2363cef2..01d7cbf3 100644
--- a/backend/internal/service/gateway_service.go
+++ b/backend/internal/service/gateway_service.go
@@ -1228,12 +1228,8 @@ func (s *GatewayService) isAccountSchedulableForWindowCost(ctx context.Context,
 
 	// 缓存未命中，从数据库查询
 	{
-		var startTime time.Time
-		if account.SessionWindowStart != nil {
-			startTime = *account.SessionWindowStart
-		} else {
-			startTime = time.Now().Add(-5 * time.Hour)
-		}
+		// 使用统一的窗口开始时间计算逻辑（考虑窗口过期情况）
+		startTime := account.GetCurrentWindowStartTime()
 
 		stats, err := s.usageLogRepo.GetAccountWindowStats(ctx, account.ID, startTime)
 		if err != nil {