diff --git a/pkg/provider/runners/difysvapi.py b/pkg/provider/runners/difysvapi.py
index ba8e5110..50dd38bd 100644
--- a/pkg/provider/runners/difysvapi.py
+++ b/pkg/provider/runners/difysvapi.py
@@ -258,7 +258,7 @@ class DifyServiceAPIRunner(runner.RequestRunner):
                 "langbot_user_message_text": plain_text,
                 "langbot_session_id": f"{query.session.launcher_type.value}_{query.session.launcher_id}_{create_time}",
                 "langbot_conversation_id": cov_id,
-                "langbot_msg_create_time": create_time,
+                "langbot_msg_create_time": f"ctime_{create_time}",
             },
             user=f"{query.session.launcher_type.value}_{query.session.launcher_id}",
             files=files,