diff --git a/package.json b/package.json
index 11b69c9..f463265 100644
--- a/package.json
+++ b/package.json
@@ -25,7 +25,7 @@
     "swig-extras": "0.0.1"
   },
   "devDependencies": {
-    "chai": "^3.4.1",
+    "chai": "^4.2.0",
     "eslint": "^2.13.1",
     "eslint-config-hexo": "^1.0.2",
     "istanbul": "^0.4.1",