In order to overcome the inherent shortcomings of traditional cascade speed control low power factor and high energy loss, a voltage type PWM cascade speed control system based on state feedback decoupling additional PI was proposed.The mathematical model of voltage type PWM inverter was deeply analyzed, and the mathematical expressions of the state feedback decoupling additional PI was derived in detail.In addition the chopper circuit IGBT selection of the speed current double closed loop PI control, the control chart of the system was obtained. Finally the simulation was proceeded by the MATLAB/Simulink software. The results proved that the control strategy not only had good dynamic and static characteristics, but also could achieve the purpose of improving power factor, reducing harmonic and saving energy.