This study is to develop a automatic design program of mechanical elements as the integrated system which can create automatically 3-dimensional solid and surface model using visualLISP. By the applying developed system to CAE system, the following objects are realized. At first, constructing the library of automatic design program for unexperienced design engineer, the 3-dimensional modeling of mechanical elements can be obtained easily. at second, the 3-dimensional model for ratchet wheel design is created by finete element model of CAE system and the optimal design condition of key way.