The crank is a crucial component in motors which withstands impact load and transmits power, and its manufacturing quality directly affects both motors’ functional ability and operational life span. By analyzing the manufacturing and machining process of cranks, a universal drilling and milling jig was designed which could be employed to process various kinds of crank.Practical manufacture and application of such new type of universal jig indicate that it is simple in configuration, accurate in locating positions and convenient in operational adjustment, thus the efficiency and quality of crank production are improved,manufacturing cost is reduced.