Abstract: Combined with the actual working condition of explosion-proof mixers used in underground coal mine, different from the traditional throttling method to control the speed of the material tank, by analyzing the working principle of the closed type pump, the strategy of adjusting the control pressure of the closed type pump to control the rotational speed of the material tank of the mixer is proposed, which is associated with the driving gear position of the vehicle so as to ensure that the material tank is in a low rotational speed state when the vehicle is running; only when the vehicle is in a neutral gear position, the high speed rotating mixing and unloading can be realized. Through the field tests, the results show that the rotational speed of the material tank installed with the speed control system can maintain a constant speed state, and will not change with the change of the throttle.