Self-testing is a means to check learning effect. Besides time-space restriction, there are many deficiencies in traditional offline self-testing. With the development of information technology, learners can have self-testing on the Internet. Self-testing on Internet, namely, web-based self-testing, overcomes time-space limitation of traditional offline self-testing, but there are still several disadvantages such as monotony and lack of interaction. In the article, a web-based self-testing system with some features of Web 2.0 is designed and implemented, aiming at overcoming the weaknesses of current online self-testing system. Firstly, taking English self-testing as an example, the framework of the system and functions of its main modules is designed according to theories of social learning and constructivism as well as the idea of Web 2.0 and the characteristics of server-side programming. Secondly, in accordance with the design above, a new system is implemented for English learners primarily by using HTML, JavaScript, PHP, and MySQL comprehensively. The role and duty of webmaster are also described briefly. To test the system, some English learners were invited randomly to use it, and feedback information was collected from them after a period of time. It is shown by feedbacks that most learners are satisfied with the system, and the system is of distinct features and favorable practicality compared with other systems, but it still needs to be improved in the design of user interface and some other details. Results in the article demonstrate that the new system can overcome the shortcomings of current systems to some extent. (Contains 1 table and 11 figures.)