Web-based mathematics competition is a popular activity in the world. The Taiwan Mathematical Olympiad (TMO) also take the Web-based competition. The study mainly reported the website system design and development for 2008 Taiwan web -based mathematics competition. The competition methods are included on-line test and pen-paper test. Participators are senior, junior high school, and elementary school students. This system was designed by diferent learning strategies and implemented the formative evaluation for the website. Researchers hope it can promote students' mathematical learning attitudes and Autonomous learning by the activity of Web-based mathematics competition.