diff --git a/api/apps/restful_apis/chat_api.py b/api/apps/restful_apis/chat_api.py
index ed1805be36..acb8f8f81a 100644
--- a/api/apps/restful_apis/chat_api.py
+++ b/api/apps/restful_apis/chat_api.py
@@ -1203,7 +1203,7 @@ async def session_completion(chat_id_in_arg=""):
                 return get_data_error_result(message=f"Cannot use specified model {chat_model_id}.")
             dia.llm_id = chat_model_id
             dia.llm_setting = chat_model_config
-        else:
+        elif not dia.llm_id:
             logging.info("empty chat_model_id in req, use default chat model.")
             _, tenant_info = TenantService.get_by_id(dia.tenant_id)
             if not tenant_info or not tenant_info.llm_id: