Abstract: A welding platform used in shielded metal arc welding, TIG, CO₂ short-circuit GMAW, single pulsed MIG/MAG and double pulsed MIG/MAG welding is established.The platform is composed of welding power, wire feeder and water cooler, which operation principles and main function are analyzed.The full digital control theories of short circuiting transfer, single pulsed and double pulsed MIG/MAG are explained in detail.Experimental results of a 400 A prototype show that it is feasible to apply different welding methods only by changing software and without changing any hardware, and the welding performance is also perfect.