Abstract: The paper introduced a mathematical model of three-phase PWM rectifier, analyzed principle of fixed switching frequency control strategy,built control structure of PWM rectifier based on inner current loop and outer voltage loop the simulated the fixed switching frequency control strategy by use of Matlab. The simulation waves of voltage at DC side and current of AC side proved the finxed swithing frequency control strategy is feasible.Meanwhile,it analyzed influence of setting key parameters of PWM rectifier on harmonic content of input current at AC side,and gave a comparatively reasonable parameter of filter inductor.