Abstract: A new method named coupling arc electrode GPCA-TIG welding is proposed,which combines coupling arc electrode and GPCA welding method,and with which deep penetration and high-speed welding can be achieved. In this paper, the weld surface appearances and weld cross-section shapes with traditional TIG,coupling arc electrode TIG and coupling arc electrode GPCA-TIG welding are studied. It is found that in the coupling arc electrode GPCA-TIG welding,the weld undercut and humping bead can be avoided,and meanwhile the weld depth increase. The results of the coupling arc electrode GPCATIG process shows that the weld depth and width increase with the decreasing of weld speed and the rising of outer nozzle position; with the increasing of arc length and flow rate of the outer gas O₂,the weld depth and width firstly increase and then decrease. The weld undercut is weaken with the increasing of welding speed,arc length and flow rate of the outer gas O₂. A good weld surface appearance can always be obtained with any outer nozzle position.