Based on working principle of forming packaging machine, it can be concluded that the profile of cam is the equidistant curve of the relative motion curve of driving and driven parts.Taking the cam blank as “paper part” and the center of the pulley as the reference, the equidistant curve of heat sealing cam will be created more conveniently and rapidly by using “Trace Curve” function of Creo Parametric.The method is applied to a certain type of forming packaging machine as an example. This method can be more regenerative by using parametric function of Creo, and it will be effectual in the condition of providing the motion principal of cam and swing link clearly. The method can be applied to obtain the key curve of two relative motion components, taking the profile curve of product manufactured by cutting tools in example.