Abstract: This paper presents an integrated simulation for full digital controlled welding system for CO₂ short circuiting welding using Matlab/Simulink, which consists of power inverter unit, digital control unit, wire feeder unit and short circuiting load unit. This full digital control inverter system for CO₂ arc welding was investigated from the point view of a whole part. The dynamic change processes of the droplet in short circuiting period and arcing period were considered in short circuiting load model, and the signals of short circuiting and arcing switching were determined using the change of arc length and the theory of electricity explosion, so the effect of full digital control was directly embodied by the behavior of the droplet and welding arc. The experimental results validated the developed simulation model, and this simulation model can be applied to the research of digital regulator rules and dynamic behavior of CO₂ short circuiting welding with full digital controlled system.