The processing of the oil path is an important procedure of motorcycle crankcase. The structural features and processing technology of some crankcase were analyzed. A simple and easy-to-use special machine was designed for polyhedral processing of drilling and reaming. The general scheme, feed drive mechanism, spindle box, fixture and lathe bed of the machine tool were focused on. The development of the tool solves the accuracy problem of simultaneous processing of multiaspect, improves machining efficiency and reduces production cost.