diff --git a/Dockerfile b/Dockerfile
index 4d696b0..3742796 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,8 +2,9 @@ FROM ubuntu
 
 RUN apt-get update \
     && apt-get install -y wget x11vnc xvfb firefox
+ENV vncpwd=xiaosong
 RUN mkdir ~/.vnc \
-    && x11vnc -storepasswd xiaosong ~/.vnc/passwd \
+    && x11vnc -storepasswd $vncpwd ~/.vnc/passwd \
     && bash -c 'echo "firefox" >> ~/.bashrc' \
     && wget http://fpdownload.macromedia.com/get/flashplayer/pdc/11.2.202.635/install_flash_player_11_linux.x86_64.tar.gz \
     && mkdir flash_player \