Abstract: The digital Push Pull CO₂ welding system is proposed.This system utilize digital power source controlled by DSP and CPLD as platform with the AC servo push-pull feeder with the low moment of inertia,fast response,and steady feed speed.The constant feeding part combine with push-pull feeding part to form the whole feeder using buffer as a linker.Consider the characteristics of the push-pull short-circuit CO₂ welding technics,the feeder speed curve,welding voltage and current waveform control program was pre-designed.According to software program,the steady push-pull CO₂ welding technics was achieved with low spatter,low heat input and uniform droplet.