Abstract: The paper discussed control strategy of cascade rectifier which was the first part of new generation of cascade non-frequency transformer. It simplified cascade rectifier model, and established a mathematical model based on single-phase rotating coordinate system. It put forward rapid balancing control strategy for DC side capacitor voltage, which decomposed switch states desired by synthesized waveform to each cascade unit. The simulation results show that the control strategy not only can make DC side capacitor voltage balance control of each cascade unit more precise, but also can control active and reactive power more effectively.