The utility model provides an ultrahigh-speed photoelectric photography system testing device for high-frequency collision of a mechanical transmission system, and relates to the field of high-speed photography. The testing device comprises a triggering module, wherein the triggering module is connected to a high-speed camera; and the triggering module, depending on one of strain variations of collision objects of the mechanical transmission system, a displacement variation between the collision objects and currents of the collision objects, can transmit a triggering signal to the high-speed camera, so as to control the high-speed camera to shoot high-speed collision.