diff --git a/backend/internal/service/rock_service.go b/backend/internal/service/rock_service.go
index 49e466b..5763252 100644
--- a/backend/internal/service/rock_service.go
+++ b/backend/internal/service/rock_service.go
@@ -344,6 +344,14 @@ func (s *RockService) AssignTokenForOrder(ctx context.Context, orderNo, expected
 		return nil, nil, err
 	}
 
+	if err == nil {
+		trimmedUID := strings.TrimSpace(expectedUID)
+		if trimmedUID != "" && token.ExpectedUID != trimmedUID {
+			token.ExpectedUID = trimmedUID
+			_ = s.db.WithContext(ctx).Model(&token).Update("expected_uid", trimmedUID).Error
+		}
+	}
+
 	// 2. 若尚未分配，锁定一个可用 Token (行锁防并发超卖)
 	if errors.Is(err, gorm.ErrRecordNotFound) {
 		err = s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {