With the development of high-band width communication technology, designersi interests seem to shift gradually from a single-user, single-domain system to a network based group-work design system. So long as one regards that the design activity develops only in a concurrent, but asynchronous fashions, it is possible to say that file transfers through computer networks have already opened up the possibility of a hands-on collaborative design process in which all participants do not have to gather in the same place.  However few CAD systems support group design work that develops in a concurrent synchronous fashion.  This paper discusses a basic model of group work CAD systems that the authors have developed for windows PCs linked with LAN.  Reviewing procedure of system operation, the authors conclude that the system could stimulate and accelerate a process of group wok design.