Using current mode PWM rectifier technology in cascade speed regulation system for motor, and eliminating the need for the dc Boost chopper of voltage type converter cascade speed regulation system, thus, simplifies the topology of the system, but also can implement the improve of power factor of the regulation system and reduce the transformer network side harmonic content. The current mode PWM inverter under the dq coordinate system is a nonlinear coupling system, which is not conducive to the controller design. This paper proposes precise linearization to linearize and decouple the original system, and constructs its pseudo linear system model, then uses sliding mode variable structure control theory to design closed loop controller of the pseudo linear system. At the same time, in the MATLAB/SIMULINK software， simulation model is established based on this control strategy. The simulation results show that the control strategy can achieve rapid, effective regulation of motor speed, at the same time, can improve power factor of the system and reduce harmonic content.