diff --git a/paddlehub/commands/serving.py b/paddlehub/commands/serving.py
index 9c2e1265aeda55d4dd60f26dc06dca52235e3bd7..fd39bf90d12a17d237ee9b22a00a05636683f4c0 100644
--- a/paddlehub/commands/serving.py
+++ b/paddlehub/commands/serving.py
@@ -206,8 +206,10 @@ class ServingCommand(BaseCommand):
         if args.sub_command == "start":
             if args.bert_service == "bert_service":
                 ServingCommand.start_bert_serving(args)
-            else:
+            elif args.bert_service is None:
                 ServingCommand.start_serving(args)
+            else:
+                ServingCommand.show_help()
         else:
             ServingCommand.show_help()