Abstract: According to the waveform control idea based on the physical nature of spatter and weld shape in CO₂ short circuit welding,this paper has studied the arc behavior such as arc-halting and arc-blo-wing-aside by its waveform sampling of current and voltage and high speed photograph.By analyzing the special arc behavior under the waveform control of the specified conditions,it is indicated that,during the arc time,the waveform should be precisely controlled instead of simply converting in order to stabilize the arc process and the whole short circuit transfer.