diff --git a/src/api_demo.py b/src/api_demo.py
index 720089fd..20350881 100644
--- a/src/api_demo.py
+++ b/src/api_demo.py
@@ -1,3 +1,4 @@
+import os
 import uvicorn
 
 from llmtuner import ChatModel, create_app
@@ -6,8 +7,8 @@ from llmtuner import ChatModel, create_app
 def main():
     chat_model = ChatModel()
     app = create_app(chat_model)
-    print("Visit http://localhost:8000/docs for API document.")
-    uvicorn.run(app, host="0.0.0.0", port=8000, workers=1)
+    print("Visit http://localhost:{}/docs for API document.".format(os.environ.get("API_PORT", 8000)))
+    uvicorn.run(app, host="0.0.0.0", port=int(os.environ.get("API_PORT", 8000)), workers=1)
 
 
 if __name__ == "__main__":