diff --git a/backend/internal/service/ratelimit_service.go b/backend/internal/service/ratelimit_service.go
index d570b92e..253faf4f 100644
--- a/backend/internal/service/ratelimit_service.go
+++ b/backend/internal/service/ratelimit_service.go
@@ -49,6 +49,7 @@ func NewRateLimitService(accountRepo AccountRepository, usageRepo UsageLogReposi
 func (s *RateLimitService) HandleUpstreamError(ctx context.Context, account *Account, statusCode int, headers http.Header, responseBody []byte) (shouldDisable bool) {
 	// apikey 类型账号：检查自定义错误码配置
 	// 如果启用且错误码不在列表中，则不处理（不停止调度、不标记限流/过载）
+	customErrorCodesEnabled := account.IsCustomErrorCodesEnabled()
 	if !account.ShouldHandleErrorCode(statusCode) {
 		log.Printf("Account %d: error %d skipped (not in custom error codes)", account.ID, statusCode)
 		return false
@@ -93,11 +94,19 @@ func (s *RateLimitService) HandleUpstreamError(ctx context.Context, account *Acc
 		s.handle529(ctx, account)
 		shouldDisable = false
 	default:
-		// 其他5xx错误：记录但不停止调度
-		if statusCode >= 500 {
+		// 自定义错误码启用时：在列表中的错误码都应该停止调度
+		if customErrorCodesEnabled {
+			msg := "Custom error code triggered"
+			if upstreamMsg != "" {
+				msg = upstreamMsg
+			}
+			s.handleCustomErrorCode(ctx, account, statusCode, msg)
+			shouldDisable = true
+		} else if statusCode >= 500 {
+			// 未启用自定义错误码时：仅记录5xx错误
 			log.Printf("Account %d received upstream error %d", account.ID, statusCode)
+			shouldDisable = false
 		}
-		shouldDisable = false
 	}
 
 	if tempMatched {
@@ -273,6 +282,16 @@ func (s *RateLimitService) handleAuthError(ctx context.Context, account *Account
 	log.Printf("Account %d disabled due to auth error: %s", account.ID, errorMsg)
 }
 
+// handleCustomErrorCode 处理自定义错误码，停止账号调度
+func (s *RateLimitService) handleCustomErrorCode(ctx context.Context, account *Account, statusCode int, errorMsg string) {
+	msg := "Custom error code " + strconv.Itoa(statusCode) + ": " + errorMsg
+	if err := s.accountRepo.SetError(ctx, account.ID, msg); err != nil {
+		log.Printf("SetError failed for account %d: %v", account.ID, err)
+		return
+	}
+	log.Printf("Account %d disabled due to custom error code %d: %s", account.ID, statusCode, errorMsg)
+}
+
 // handle429 处理429限流错误
 // 解析响应头获取重置时间，标记账号为限流状态
 func (s *RateLimitService) handle429(ctx context.Context, account *Account, headers http.Header) {
diff --git a/frontend/src/components/account/BulkEditAccountModal.vue b/frontend/src/components/account/BulkEditAccountModal.vue
index 51ad32d1..9ccf6130 100644
--- a/frontend/src/components/account/BulkEditAccountModal.vue
+++ b/frontend/src/components/account/BulkEditAccountModal.vue
@@ -778,6 +778,16 @@ const addPresetMapping = (from: string, to: string) => {
 const toggleErrorCode = (code: number) => {
   const index = selectedErrorCodes.value.indexOf(code)
   if (index === -1) {
+    // Adding code - check for 429/529 warning
+    if (code === 429) {
+      if (!confirm(t('admin.accounts.customErrorCodes429Warning'))) {
+        return
+      }
+    } else if (code === 529) {
+      if (!confirm(t('admin.accounts.customErrorCodes529Warning'))) {
+        return
+      }
+    }
     selectedErrorCodes.value.push(code)
   } else {
     selectedErrorCodes.value.splice(index, 1)
@@ -794,6 +804,16 @@ const addCustomErrorCode = () => {
     appStore.showInfo(t('admin.accounts.errorCodeExists'))
     return
   }
+  // Check for 429/529 warning
+  if (code === 429) {
+    if (!confirm(t('admin.accounts.customErrorCodes429Warning'))) {
+      return
+    }
+  } else if (code === 529) {
+    if (!confirm(t('admin.accounts.customErrorCodes529Warning'))) {
+      return
+    }
+  }
   selectedErrorCodes.value.push(code)
   customErrorCodeInput.value = null
 }
diff --git a/frontend/src/components/account/CreateAccountModal.vue b/frontend/src/components/account/CreateAccountModal.vue
index 5833632b..1a4edaf1 100644
--- a/frontend/src/components/account/CreateAccountModal.vue
+++ b/frontend/src/components/account/CreateAccountModal.vue
@@ -1976,6 +1976,16 @@ const addPresetMapping = (from: string, to: string) => {
 const toggleErrorCode = (code: number) => {
   const index = selectedErrorCodes.value.indexOf(code)
   if (index === -1) {
+    // Adding code - check for 429/529 warning
+    if (code === 429) {
+      if (!confirm(t('admin.accounts.customErrorCodes429Warning'))) {
+        return
+      }
+    } else if (code === 529) {
+      if (!confirm(t('admin.accounts.customErrorCodes529Warning'))) {
+        return
+      }
+    }
     selectedErrorCodes.value.push(code)
   } else {
     selectedErrorCodes.value.splice(index, 1)
@@ -1993,6 +2003,16 @@ const addCustomErrorCode = () => {
     appStore.showInfo(t('admin.accounts.errorCodeExists'))
     return
   }
+  // Check for 429/529 warning
+  if (code === 429) {
+    if (!confirm(t('admin.accounts.customErrorCodes429Warning'))) {
+      return
+    }
+  } else if (code === 529) {
+    if (!confirm(t('admin.accounts.customErrorCodes529Warning'))) {
+      return
+    }
+  }
   selectedErrorCodes.value.push(code)
   customErrorCodeInput.value = null
 }
diff --git a/frontend/src/components/account/EditAccountModal.vue b/frontend/src/components/account/EditAccountModal.vue
index 3b36cfbf..7cb740bd 100644
--- a/frontend/src/components/account/EditAccountModal.vue
+++ b/frontend/src/components/account/EditAccountModal.vue
@@ -936,6 +936,16 @@ const addPresetMapping = (from: string, to: string) => {
 const toggleErrorCode = (code: number) => {
   const index = selectedErrorCodes.value.indexOf(code)
   if (index === -1) {
+    // Adding code - check for 429/529 warning
+    if (code === 429) {
+      if (!confirm(t('admin.accounts.customErrorCodes429Warning'))) {
+        return
+      }
+    } else if (code === 529) {
+      if (!confirm(t('admin.accounts.customErrorCodes529Warning'))) {
+        return
+      }
+    }
     selectedErrorCodes.value.push(code)
   } else {
     selectedErrorCodes.value.splice(index, 1)
@@ -953,6 +963,16 @@ const addCustomErrorCode = () => {
     appStore.showInfo(t('admin.accounts.errorCodeExists'))
     return
   }
+  // Check for 429/529 warning
+  if (code === 429) {
+    if (!confirm(t('admin.accounts.customErrorCodes429Warning'))) {
+      return
+    }
+  } else if (code === 529) {
+    if (!confirm(t('admin.accounts.customErrorCodes529Warning'))) {
+      return
+    }
+  }
   selectedErrorCodes.value.push(code)
   customErrorCodeInput.value = null
 }
diff --git a/frontend/src/i18n/locales/en.ts b/frontend/src/i18n/locales/en.ts
index f0e7db55..e23b6bcc 100644
--- a/frontend/src/i18n/locales/en.ts
+++ b/frontend/src/i18n/locales/en.ts
@@ -1203,6 +1203,10 @@ export default {
       customErrorCodesHint: 'Only stop scheduling for selected error codes',
       customErrorCodesWarning:
         'Only selected error codes will stop scheduling. Other errors will return 500.',
+      customErrorCodes429Warning:
+        '429 already has built-in rate limit handling. Adding it to custom error codes will disable the account instead of temporary rate limiting. Are you sure?',
+      customErrorCodes529Warning:
+        '529 already has built-in overload handling. Adding it to custom error codes will disable the account instead of temporary overload marking. Are you sure?',
       selectedErrorCodes: 'Selected',
       noneSelectedUsesDefault: 'None selected (uses default policy)',
       enterErrorCode: 'Enter error code (100-599)',
diff --git a/frontend/src/i18n/locales/zh.ts b/frontend/src/i18n/locales/zh.ts
index ecdcb13f..e1cf78e9 100644
--- a/frontend/src/i18n/locales/zh.ts
+++ b/frontend/src/i18n/locales/zh.ts
@@ -1339,6 +1339,10 @@ export default {
       customErrorCodes: '自定义错误码',
       customErrorCodesHint: '仅对选中的错误码停止调度',
       customErrorCodesWarning: '仅选中的错误码会停止调度，其他错误将返回 500。',
+      customErrorCodes429Warning:
+        '429 已有内置的限流处理机制。添加到自定义错误码后，将直接停止调度而非临时限流。确定要添加吗？',
+      customErrorCodes529Warning:
+        '529 已有内置的过载处理机制。添加到自定义错误码后，将直接停止调度而非临时标记过载。确定要添加吗？',
       selectedErrorCodes: '已选择',
       noneSelectedUsesDefault: '未选择（使用默认策略）',
       enterErrorCode: '输入错误码 (100-599)',