Abstract: The arc behavior of MAG welding with strip electrode was investigated using a high speed CCD camera system and a current and voltage acquisition set. The results show the welding arc is not cylindrical symmetry, it has a pronounced elliptical shape at the strip electrode end, and tends to be more circular whereas at the workpiece. There are several arcs generated simultaneously at the strip electrode end with low current, and they move along the strip electrode with no regularity. With the increase of welding current, only one arc is generated. It waves left and right along the strip electrode end, and the amplitude of its motion decreases gradually. Finally it burns steadily at high current with high stiffness. The waveforms of welding current and arc voltage can reflect the arc motion.