Abstract: This paper introduces a new structure of CAPP system by means of object-oriented method. The concept of class is used for the research of CAPP, and the form feature, machine tool, jig, cutting tool, cutting parameter are defined as the different dasses. The procedure of process planning is highly abstracted and the separation is realized between program structure and data. The CAPP system is programmed in objed-oriented language C++ and runs on SUN4 workstation.