Abstract: The law of uniform velocity motion of the push rod is used in cam mechanism commonly. In order to improve the motion characteristics of cam mechanism under law of uniform velocity motion, enhance the stability of cam mechanism, a kind of modified strategy is proposed in this paper, a combined motion law is designed. It can satisfy the requirement that the push rod moves according to the law of uniform velocity motion, and the accelerated speed does not change abruptly, the rigid impact and the flexible impact in the movement of the push rod are eliminated as well. Kinematics simulation of cam mechanism is carried out by using Matlab, the accurate contour curve design of cam mechanism is designed with Pro/E and Matlab. The simulation results show that the motion characteristics of the law of uniform velocity motion have been significantly improved.