The invention provides a friction driving mechanism. The friction driving mechanism comprises a motor, a tensioning device, friction wheels, a driving shaft, a connecting seat and a bearing subassembly, wherein the friction wheel is fixed on the driving shaft; the motor is fixed on the connecting seat; and the bearing subassembly is arranged on the driving shaft and is connected with the tensioning device through a steel wire rope or a steel belt. The two cylindrical friction wheels are tightly pressed on a guide track, and the motor drives the friction wheels to rotate, so that the friction driving mechanism walks along a fixed track in a self-driving manner; and after being worn, a transmission mechanism can be recovered by only adjusting the tensioning device. The structure mode of the friction driving mechanism is easy to implement; the friction driving mechanism is economical and reliable, runs stably and vibrates slightly; and by the tensioning device, a track car can stably pass through a corner with the small turning radius, and easily runs reversely at high speed.