Abstract: Along with the wide use of computer-aided design systems and the rapid advance in the research on computer supported cooperative work, people are integrating CAD with CSCW technologies to develop computer supported cooperative design systems. This paper introduces the basic model of CSCW application, then presents system structure and some key techniques of CoopCAD system in detail, which is based on the replicated sharing application technology in CSCW. Finally, this paper gives an example of CoopCAD's application.