diff --git a/main.py b/main.py
index 43e5205..b04a40b 100644
--- a/main.py
+++ b/main.py
@@ -2739,9 +2739,9 @@ async def fastapi_run_project_by_date(network: str, querydate: str) -> str:
 
         bg_start_time, bg_end_time = time_api.parse_beijing_date_range(querydate)
 
-        bg_start_time_str = str(bg_start_time)
+        bg_start_time_str = bg_start_time.strftime("%Y-%m-%dT%H:%M:%SZ")
         print(f"bg_start_time_str: {bg_start_time_str}")
-        bg_end_time_str = str(bg_end_time)
+        bg_end_time_str = bg_end_time.strftime("%Y-%m-%dT%H:%M:%SZ")
         print(f"bg_end_time_str: {bg_end_time_str}")
 
         result = run_simulation_ex(name=network, simulation_type='realtime', start_datetime=bg_start_time_str, end_datetime=bg_end_time_str)