Abstract: In this paper,the arc burning process in the wire arc spray is analyzed with high-speed digital camera.The arc process is "igniting-burning-extinguished-igniting".It isn't always in burning state and often extinguished frequently.There are two kinds of reasons for extinguish arc.The first one is that the two metal wires directly contact to form a short circuit.The second one is that the imperfect melted metal dragged the arc long,and then this part metal is melted and broken away from the metal wires tip.It is testified that the arc has the elliptical shape.This shape is favorable for heating the metal particles.If we can control the metal wires state,the properties of coatings would be improved.