Torque is generated based on the gear rack transmission and the energy storage characteristics of spring in this slow torque outputs device. Through the combined application of the hydraulic cylinder and the oneway valve and a flow control valve, target of slow output of hightorque was achieved. In view of the calculation formula of the hydraulic cylinder deficiency in non constant flow, the quantitative analysis could not be carried out, a mathematical model was established for the velocity and flow volume of the hydraulic cylinder in orifice outflow in non constant load to get the time of torque output.Through theoretical analysis and experimental verification, the target of slow output of hightorque was achieved, which also verified the correctness of the derived mathematical model.The devicehasthe advantages of simple structure, high transmission efficiency, high torque output and so on,which can preventharmcaused by hightorque output device whenother component failed.