Abstract: Based on the high-speed video system with electrical signals analyzer in synchronous,the electrical signals and the photographs of molten droplet under certain welding parameters were collected,the electrical arc shape and droplet transfer pattern of welding process in twin-wire pulsed MAG welding were studied.It is observed that when the pulse current exerted on the front wire and the rear wire by turns,the shape of arcs presents the clock cover form,and has no influence on each other.When the pulse current exerted on the front wire and the rear wire in phase,the arcs attract each other and the arc is incorporated as a peach.The weld appearance of the synchronous pulse current is good and the concomitant is great noise and smog.The weld appearance of the alternating pulse current is tolerable.