In view of the common mode voltage and current caused by the PWM voltage output of the inverter of the photovoltaic pump system, which often causes the pump motor failure, on the basis of analyzing the mechanism of the common mode voltage and current generated by the PWM inverter driving motor system. The common point of the filter capacitor is connected back to the LC filter on the negative side of the photovoltaic bus, so that the common mode voltage and current are suppressed. The LC filter changes the input state of the motor side. The selection of filtering parameters is optimized by analyzing the influence of the PWM output LC filtering method on the induction motor control system, and the experiments of the above research are carried out. The results show that the parameter selection method is correct and effective.