The determination for three phase PWM rectifier main circuit parameters is the key part to implement its efficient operation and keep good dynamic characteristics.But there is a certain blindness about the existing selecting methods.In this paper,a inductor value design method to satisfy steady-state performances and restrain harmonic current and a capacitor selection to meet dc voltage tracking effect and ensure voltage loop anti-interference characteristics are proposed. The mathematical model of the main circuit is based on the three phase voltage source PWM rectifier.The method can solve the blindness of the main circuit parameters selection.The simulation and experimental results are presented to verify the proposed method.