diff --git a/init_priv.sh b/init_priv.sh
index 8cdd22d..3ede419 100755
--- a/init_priv.sh
+++ b/init_priv.sh
@@ -109,6 +109,8 @@ configure_tmux() {
 }
 
 configure_docker() {
+    command_exists docker && return
+
     if confirm_action "要安装 docker 吗？" "N"; then
         # 卸载旧版本
         sudo apt remove docker docker-engine docker.io
diff --git a/utils.sh b/utils.sh
index 68c59c2..fee831a 100755
--- a/utils.sh
+++ b/utils.sh
@@ -53,6 +53,10 @@ confirm_action() {
     [[ $response =~ ^[Yy]$ ]]
 }
 
+command_exists() {
+    command -v "$@" >/dev/null 2>&1;
+}
+
 # ============================================================
 
 check_google_access