Abstract: A PWM method named present pulse control for inverter, which is based on the treatment for instantaneous signal of welding current, was proposed in this paper. Rapid regulation without overshoot of welding current can be realized in the whole range of arc load. It meets requirments of varied welding processes and ensures the performance reliability of inverter. The basic principle of feedback control and mathematical analysis of the static and dynamic property, as well as the experiment results were described in this paper.