Using SiC MOSFET and Si-based Schottky diode as main power devices,a 400 A class pulse MIG inverter welding power supply with ARM(advanced RISC machines) as the main control chip is developed. A SiC MOSFET driver with protection functions is designed according to the characteristics of SiC MOSFET power devices and the inverter welding power supply. The full bridge inverter structure is adopted in the main circuit,and the full bridge rectifier structure is adopted in the rectifier circuit. The results show that the output current waveform of the SiC MOSFET pulse MIG inverter welding power source is stable and controllable,the dynamic response performance is good,and the welding effect is excellent.