diff --git a/src/index.js b/src/index.js
index 9447ec5fffe7b9e70c93d5b64eebff73b93e744a..461b3fa15c40eb23c1b4c6a217fcdf14804dbfed 100644
--- a/src/index.js
+++ b/src/index.js
@@ -26,7 +26,8 @@ class UniID {
     config
   } = {}) {
     this._clientInfo = context ? parseContext(context) : clientInfo
-    this.config = config || this._getOriginConfig()
+    this._config = config
+    this.config = this._getOriginConfig()
     this.interceptorMap = new Map()
     if (uniIDConfig.hasFile('custom-token.js')) {
       this.setInterceptor('customToken', require(uniIDConfig.resolve('custom-token.js')))
@@ -59,6 +60,9 @@ class UniID {
   }
 
   _getOriginConfig () {
+    if (this._config) {
+      return this._config
+    }
     if (uniIDConfig.hasFile('config.json')) {
       let configContent
       try {