diff --git a/README.md b/README.md
index da0cdaf9..a70c73a5 100644
--- a/README.md
+++ b/README.md
@@ -107,3 +107,4 @@ Python `2.7`, `3.3`, `3.4`, `3.5`, and `3.6`.
 - [《ApiTestEngine 演进之路（1）搭建基础框架》](http://debugtalk.com/post/ApiTestEngine-1-setup-basic-framework/)
 - [《ApiTestEngine 演进之路（2）探索优雅的测试用例描述方式》](http://debugtalk.com/post/ApiTestEngine-2-best-testcase-description/)
 - [《ApiTestEngine 演进之路（3）测试用例中实现 Python 函数的定义》](http://debugtalk.com/post/ApiTestEngine-3-define-functions-in-yaml-testcases/)
+- [《ApiTestEngine 演进之路（4）测试用例中实现 Python 函数的调用》](http://debugtalk.com/post/ApiTestEngine-4-call-functions-in-yaml-testcases/)