diff --git a/backend/Dockerfile b/backend/Dockerfile
index 44c53f0..027d89a 100644
--- a/backend/Dockerfile
+++ b/backend/Dockerfile
@@ -25,7 +25,7 @@ ENV UV_LINK_MODE=copy
 RUN --mount=type=cache,target=/root/.cache/uv \
     --mount=type=bind,source=uv.lock,target=uv.lock \
     --mount=type=bind,source=pyproject.toml,target=pyproject.toml \
-    uv sync --frozen --no-install-project
+    uv sync --frozen --no-install-project -i https://pypi.tuna.tsinghua.edu.cn/simple
 
 ENV PYTHONPATH=/app