diff --git a/docs/Overview/Installation.rst b/docs/Overview/Installation.rst
index 229a274..860ec97 100644
--- a/docs/Overview/Installation.rst
+++ b/docs/Overview/Installation.rst
@@ -12,7 +12,7 @@ For testing purposes, you can install it using:
 
 .. code:: console
 
-    $ pip install -i https://test.pypi.org/simple/ abl
+    $ pip install -i https://test.pypi.org/simple/ --extra-index-url https://mirrors.nju.edu.cn/pypi/web/simple/ abl
 
 Alternatively, to install ABL by source code, 
 sequentially run following commands in your terminal/command line.
diff --git a/docs/README.rst b/docs/README.rst
index 40e230d..cfd44a6 100644
--- a/docs/README.rst
+++ b/docs/README.rst
@@ -24,7 +24,7 @@ For testing purposes, you can install it using:
 
 .. code:: console
 
-    $ pip install -i https://test.pypi.org/simple/ abl
+    $ pip install -i https://test.pypi.org/simple/ --extra-index-url https://mirrors.nju.edu.cn/pypi/web/simple/ abl
 
 Alternatively, to install ABL by source code, 
 sequentially run following commands in your terminal/command line.