To meet the demand of that the waveform control welding machine controlling the waveform of the arc voltage and arc current, need to further improve the working frequency of the inverter power source and reduce switching loss, switching stress and electromagnetic interference. The parameters of soft-switching inverter’s main circuit, witch make the working state with zero-voltage and zero-current switching, is designed. First, the working principle of the FB-ZVZCS-PWM inverter is analyzed. And the constraint equation of the main circuit’s parameters is obtained, it provide the basis for the calculation of the main circuit’s parameters. According to the requirements of the working condition of inverter and the time sequence of PWM, the value of the block capacitor Cx is obtained. And the satiable inductor, witch improve the rise speed of the short circuit current and the descending speed of the necking current, is designed. Second, the simulation model of the satiable inductor is designed. And the simulation model of the FB-ZVZCS-PWM inverter is established. It verified the correctness of the theoretical analysis and the parameter design.