The roller gear indexing cam has irreplaceable superiority in the high-accuracy and high-speed indexing motion, but it can not keep the system’s good dynamic characteristics to improve machining accuracy of cam only. This paper studies the dynamic simulation of the roller gear indexing cam by means of virtual prototype technology, rigid multi-body dynamics, and contact mechanics, and the influences of this system’s parameters on dynamic responds of the mechanism. These works are valuable for designers, makers and users to optimal design, test, and make the mechanism, and give a new method for studying dynamics of roller gear indexing cam.