Abstract:To the automobile and motorcycle crank pin hole, an automatic cycle crankshaft boring machine with five station was developed for its processing. The mechanical structure was designed for the automatic cycle crankshaft boring machine; based on the processing technology requirements of the crank pin hole, some main components such as positioning & clamping device and center distance fine adjustment mechanism were designed and analyzed; the processing cycle and control system were designed for the circular crankshaft lathe, and the control program flow was given. The successful application shows the rationality of the designed crankshaft boring machine.