This paper deals with the development of an expert process design system interfaced with CAD for porismatic parts in injection mold manufacture. The developed CAD/CAPP system consists of two modules such as CAD interface module and process design module. Parts are represented using AutoCAD system on the IBM PC/AT. CAD interface module recognizes form features and manufacturing features of the part using form feature recognition algorithm and manufacturing feature recognition rule base. Process design module selects operations and determines machine tools, cutting tools and operation sequencing by using knowledge base which is acquired from expert process planners. A case study is implemented to evaluate feasibilities of the function of the proposed system. The CAD/CAPP system can improve the efficiency of process design activities and reduce the time required for process design.