diff --git a/lightrag/llm/openai.py b/lightrag/llm/openai.py
index d9939809..68b92e83 100644
--- a/lightrag/llm/openai.py
+++ b/lightrag/llm/openai.py
@@ -81,6 +81,8 @@ def create_openai_async_client(
 
     if base_url is not None:
         merged_configs["base_url"] = base_url
+    else:
+        merged_configs["base_url"] = os.environ["OPENAI_API_BASE"]
 
     return AsyncOpenAI(**merged_configs)