The machining principle of three-dimensional edge grinding for great curvature automobile rearview mirror was introduced. The relation between the parameters of a part like cam was deduced, which could be used to implement the processing scheme. Based on the result, the part like cam suitable for the automobile rearview mirror with a radius of 1 200 mm was created in UG. The mechanism, consisted of the part like cam and cuspidal cylinder, changes the situation that the existing profiling edge grinding machine can only be used to produce parts in plane geometry shape, implementing the three-dimensional edge grinding of the profiling edge grinding machine.