The elasto-hydrodynamic lubrication theory was used for setting up transmission characteristics of traction calculation model. The dynamic simulation model of this system was established by using Matlab. From simulation results, traction friction pair was equivalent to traditional role of main gearbox or torque converter with a buffer function in the transmission process. When gave a input speed and a loading force, the smaller the speed ratio was, the greater the output speed was. But the time of achieving stabilization was longer at the same time, the response time of output torque and output angular acceleration was longer. The simulation results reflected the dynamics characteristic of traction transmission devices. It is provided an accurate method for hydraulic clamp traction transmission devices.