diff --git a/docker/Dockerfile b/docker/Dockerfile
index 53979d36..c9cd4176 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -7,7 +7,8 @@ ENV PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin \
     LANG=zh_CN.UTF-8 \
     SHELL=/bin/bash \
     PS1="\u@\h:\w \$ " \
-    QL_DIR=/ql
+    QL_DIR=/ql \
+    QL_BRANCH=${QL_BRANCH}
 WORKDIR ${QL_DIR}
 RUN set -x \
     && sed -i 's/dl-cdn.alpinelinux.org/mirrors.tuna.tsinghua.edu.cn/g' /etc/apk/repositories \