Abstract: In this work, a theory of the generating method of cam profiles by the sewing motion of the crank-rocker mechanism is creatively developed. After being discussed the reasonable dimensions and characters of the motion of bar mechanism used in the generating equipment, the obtained motions and other parameters of cam mechanism are explained. Especially the influence of diameter difference between the grinding wheel and the roller to the cam profile errors and its correcting methods are analyzed. With a short description of the cam generating equipment, some experimental data and results are given.