diff --git a/infra/docker/nginx-entrypoint.sh b/infra/docker/nginx-entrypoint.sh
index 88c25d45c..a0ca7653b 100755
--- a/infra/docker/nginx-entrypoint.sh
+++ b/infra/docker/nginx-entrypoint.sh
@@ -2,16 +2,21 @@
 # Select nginx config based on APP_ENV (staging/production).
 # Both configs are baked into the image at well-known paths.
 # nginx reads config only at startup, so symlink before exec.
+# 注意：基础镜像 /etc/nginx/conf.d/default.conf 是普通文件（非 symlink/目录），
+# alpine busybox ln -sf 在 target 已存在且为普通文件时行为不稳定（会尝试在
+# target 目录下建子链接），必须先 rm 再 ln 才能正确替换。
 set -e
 
 NGINX_CONF_DIR="/etc/nginx/conf.d"
 
 case "${APP_ENV:-production}" in
   staging)
-    ln -sf /etc/nginx/nginx-staging.conf "$NGINX_CONF_DIR/default.conf"
+    rm -f "$NGINX_CONF_DIR/default.conf"
+    ln -s /etc/nginx/nginx-staging.conf "$NGINX_CONF_DIR/default.conf"
     ;;
   *)
-    ln -sf /etc/nginx/nginx-production.conf "$NGINX_CONF_DIR/default.conf"
+    rm -f "$NGINX_CONF_DIR/default.conf"
+    ln -s /etc/nginx/nginx-production.conf "$NGINX_CONF_DIR/default.conf"
     ;;
 esac