diff --git a/internal/repository/transaction_repository.go b/internal/repository/transaction_repository.go
index 8578e70..5533842 100644
--- a/internal/repository/transaction_repository.go
+++ b/internal/repository/transaction_repository.go
@@ -264,7 +264,11 @@ func (r *TransactionRepository) applyFilters(query *gorm.DB, filter TransactionF
 
 	// Entity filters
 	if filter.CategoryID != nil {
-		query = query.Where("category_id = ?", *filter.CategoryID)
+		// Include sub-categories
+		var subCategoryIDs []uint
+		r.db.Model(&models.Category{}).Where("parent_id = ?", *filter.CategoryID).Pluck("id", &subCategoryIDs)
+		ids := append(subCategoryIDs, *filter.CategoryID)
+		query = query.Where("category_id IN ?", ids)
 	}
 	if filter.AccountID != nil {
 		query = query.Where("account_id = ? OR to_account_id = ?", *filter.AccountID, *filter.AccountID)
diff --git a/internal/service/ai_bookkeeping_service.go b/internal/service/ai_bookkeeping_service.go
index 66ec7b1..9188ea5 100644
--- a/internal/service/ai_bookkeeping_service.go
+++ b/internal/service/ai_bookkeeping_service.go
@@ -445,31 +445,45 @@ func extractCustomPrompt(text string) string {
 
 // ParseIntent extracts transaction parameters from text
 // Requirements: 7.1, 7.5, 7.6
-func (s *LLMService) ParseIntent(ctx context.Context, text string, history []ChatMessage) (*AITransactionParams, string, error) {
-
+func (s *LLMService) ParseIntent(ctx context.Context, text string, history []ChatMessage, userID uint) (*AITransactionParams, string, error) {
 	if s.config.OpenAIAPIKey == "" || s.config.OpenAIBaseURL == "" {
 		// No API key, return simple parsing result
 		simpleParams, simpleMsg, _ := s.parseIntentSimple(text)
 		return simpleParams, simpleMsg, nil
 	}
 
+	// Fetch user categories for prompt context
+	var categoryNamesStr string
+	if categories, err := s.categoryRepo.GetAll(userID); err == nil && len(categories) > 0 {
+		var names []string
+		for _, c := range categories {
+			names = append(names, c.Name)
+		}
+		categoryNamesStr = strings.Join(names, "/")
+	}
+
 	// Build messages with history
 	var systemPrompt string
 
 	// 检查是否有自定义 System/Persona prompt（用于财务建议等场景）
-	// 如果有，直接使用自定义 prompt 覆盖默认记账 prompt
 	if customPrompt := extractCustomPrompt(text); customPrompt != "" {
 		systemPrompt = customPrompt
 	} else {
 		// 使用默认的记账 prompt
 		todayDate := time.Now().Format("2006-01-02")
+
+		catPrompt := "2. 分类：根据内容推断，如\"奶茶/咖啡/吃饭\"=餐饮"
+		if categoryNamesStr != "" {
+			catPrompt = fmt.Sprintf("2. 分类：必须从以下已有分类中选择最匹配的一项：[%s]。例如\"晚餐\"应映射为列表中存在的\"餐饮\"。如果列表无匹配项，则根据常识推断。", categoryNamesStr)
+		}
+
 		systemPrompt = fmt.Sprintf(`你是一个智能记账助手。从用户描述中提取记账信息。
 
 今天的日期是%s
 
 规则：
 1. 金额：提取数字，如"6元"=6，"十五"=15
-2. 分类：根据内容推断，如"奶茶/咖啡/吃饭"=餐饮，"打车/地铁"=交通，"买衣服"=购物
+%s
 3. 类型：默认expense(支出)，除非明确说"收入/工资/奖金/红包"
 4. 金额：提取明确的数字。如果用户未提及具体金额（如只说"想吃炸鸡"），amount字段必须返回 0
 5. 日期：默认使用今天的日期（%s），除非用户明确指定其他日期
@@ -480,7 +494,8 @@ func (s *LLMService) ParseIntent(ctx context.Context, text string, history []Cha
 
 示例（假设今天是%s）：
 用户："买了6块的奶茶"
-返回：{"amount":6,"category":"餐饮","type":"expense","note":"奶茶","date":"%s","message":"记录：餐饮支出6元，奶茶"}`, todayDate, todayDate, todayDate, todayDate)
+返回：{"amount":6,"category":"餐饮","type":"expense","note":"奶茶","date":"%s","message":"记录：餐饮支出6元，奶茶"}`,
+			todayDate, catPrompt, todayDate, todayDate, todayDate)
 	}
 
 	messages := []ChatMessage{
@@ -915,7 +930,7 @@ func (s *AIBookkeepingService) ProcessChat(ctx context.Context, userID uint, ses
 	isSpendingAdvice := s.isSpendingAdviceIntent(message)
 
 	// Parse intent for transaction
-	params, responseMsg, err := s.llmService.ParseIntent(ctx, message, session.Messages[:len(session.Messages)-1])
+	params, responseMsg, err := s.llmService.ParseIntent(ctx, message, session.Messages[:len(session.Messages)-1], userID)
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse intent: %w", err)
 	}