diff --git a/packages/mitmproxy/src/json.js b/packages/mitmproxy/src/json.js
index cf0a230..a16fae3 100644
--- a/packages/mitmproxy/src/json.js
+++ b/packages/mitmproxy/src/json.js
@@ -1,4 +1,5 @@
 let JSON5 = require('json5')
+const log = require('util/util.log')
 if (JSON5.default) {
   JSON5 = JSON5.default
 }
@@ -14,6 +15,7 @@ module.exports = {
     try {
       return JSON5.stringify(obj)
     } catch (e) {
+      log.warn('转换为JSON字符串失败, error:', e, ', obj:', obj)
       return obj.toString()
     }
   }