In order to overcome the inherent shortcomings of traditional cascade speed regulation such as low power factor and great energy loss, the currentmode PWM cascade speed regulation system based on inverse system decoupling additional variable structure control was proposed..In order to enhance the robustness of the system, the inverse system decoupling additional variable structure control strategy was adopted in the PWM inverter, and the control strategy was deduced in detail. Combined with the speed and current double closed loop PI control adopted by the chopper circuit, the control chart of the system was obtained. Finally the effectiveness of the control strategy was simulated and verified by using Matlab. The results proved that the system not only had good dynamic performance, but also improved the power factor, reduced the harmonic and saved the energy.