Abstract: Web applications have grown faster and faster and become more and more complex.How to confirm the quality and the reliability of these systems has been ever important.This paper proposed a test case automatic execution system，which based on a X-Case structure，which authors designed using Extensible Markup Language（XML）.It can perform like a real user in the terminal system to test any Web application.The system is characterized by high reusability of test cases，only the first testing of test cases needs to be generated.For some of the changes of a Web system，authors just need to change the relevant parameter of X-Case and do the test procedure again.This system supports parts of the test data auto-generating and does the test well no matter the pages are static or dynamic.