diff --git a/packages/uni-mp-weixin/lib/uni.compiler.js b/packages/uni-mp-weixin/lib/uni.compiler.js
index e949cd902bd8e3ad31703595a917c9f10de03c6a..4a3c0ac4d32bfe1bd106d7ee1a2db0beaeb06c52 100644
--- a/packages/uni-mp-weixin/lib/uni.compiler.js
+++ b/packages/uni-mp-weixin/lib/uni.compiler.js
@@ -109,7 +109,7 @@ module.exports = {
     try {
       // TODO 使用 getPlatformExts 在单元测试报错，改从 state.options.platform 判断
       const { getPlatformExts } = require('@dcloudio/uni-cli-shared')
-      let styleExtname = getPlatformExts().style
+      const styleExtname = getPlatformExts().style
       const styleFile = resourcePath.replace(ownerName + extname, componentName + styleExtname)
       const styleContent = generateCssCode(ownerName + styleExtname)