In order to study the feasibility of the soft recoil gun recoil device movement, according to the force of the soft recoil gun, the differential equation of the soft recoil gun recoil device was established, and the dynamic characteristics of the soft recoil gun were studied by Simulink simulation. The results show that the method can obtain the motion law of squat portion of the whole motion cycle, and the result accords with the motion law of recoil device of the soft recoil gun.