diff --git a/pt_site/apps.py b/pt_site/apps.py
index ebfca70..841db62 100644
--- a/pt_site/apps.py
+++ b/pt_site/apps.py
@@ -36,7 +36,7 @@ class PtSiteConfig(AppConfig):
 
     def ready(self):
         # 环境变量不存在，说明数据库还未初始化，先跳过初始化站点数据
-        if os.getenv('CONTAINER_ALREADY_STARTED'):
+        if os.path.exists('CONTAINER_ALREADY_STARTED_PLACEHOLDER'):
             post_migrate.connect(app_ready_handler, sender=self)
         else:
             logger.info('第一次启动容器，初始化数据库中')
diff --git a/start.sh b/start.sh
index 8c3e1aa..d7f2cb1 100644
--- a/start.sh
+++ b/start.sh
@@ -19,10 +19,16 @@ if [ ! -e $CONTAINER_ALREADY_STARTED ]; then
   ls -l
   echo "安装pip依赖"
   pip install -r requirements.txt
-  echo "初始化数据库"
+  echo "系统初始化中"
   python manage.py makemigrations
-  python manage.py migrate
-  python manage.py loaddata pt.json
+  if [ ! -f db/db.sqlite3 ]; then
+    echo '数据库不存在，初始化数据库'
+    python manage.py migrate
+    python manage.py loaddata pt.json
+  else
+    echo '数据库已存在，同步数据库结构'
+    python manage.py migrate
+  fi
   touch $CONTAINER_ALREADY_STARTED
   echo "创建超级用户"
   DJANGO_SUPERUSER_USERNAME=$DJANGO_SUPERUSER_USERNAME