diff --git a/ticc.js b/ticc.js
index ac1d59e..b454d37 100644
--- a/ticc.js
+++ b/ticc.js
@@ -518,11 +518,11 @@ class TicCrypto {
       let part5 = parseInt(pathHash.slice(30, 32), 16)
       path = `${part0}'/${part1}/${part2}/${part3}/${part4}/${part5}`
     } else {
-      // 本方法也可用来生成默认的第0个路径，例如 "m/44'/0'/0'/0/0"
-      path = "0'/0/0"
+      // 本方法也可用来生成默认路径，例如 "m/44'/0'/0'/0/0"
+      path = "0'/0" // Account'/Change
     }
     // 注意，如果 pathIndex 为 undefinded 或者非数字，得出的 path 是不同的！
-    pathIndex = parseInt(pathIndex)
+    pathIndex = parseInt(pathIndex) || 0
     if (0 <= pathIndex && pathIndex <= 0x7fffffff) {
       path += `/${pathIndex}`
     }