In this research we developed a pedagogical content knowledge (PCK) sharing system to support a teaching practicum course which was taken by 49 students being trained to become Chinese language arts teachers at secondary schools. The system dynamically collects and stores PCK items created by students as the course proceeds through the entire semester. The items include lesson plans, student worksheets, handouts, tests, journals and video clips of students' teaching practices. These items are structured around an underlying content knowledge (CK) database which stores more than 200 pieces of writings and related knowledge. As such, each PCK item is put in a meaningful context for evaluation and discussion. Related functionalities provided by the system include My Wok Area, online journals, message boxes and a discussion forum. Results from user interviews, a questionnaire survey and observation about users' on-line behavior all confirm that this system helps the course to function much more effectively.