Based on the research and analysis of running condition and manufacture process of cylindrical cam with oscillating follower, as the widely used plane expansion method for cylindrical cams trough-outline in the design and manufacture processes, the inaccuracy was pointed out. To improve the current plane expansion method, a new system named “3D curve expansion” was proposed for cylindrical cam trough-outline design. This system takes advantage of the expansion on cylindrical cursive surface and coordinates transformation of motion curves based on the movement of oscillating follower. By applying this “3D curve expansion” system to the cylindrical cam design and manufacturing, a set of effective methodology was established.