Abstract: In order to obtain the optimal parameters for aluminum alloy fusion of Tri-arc double wires and achieve high efficiency arc fusion,the behaviors of the arcs and metal transfer were recorded by high-speed video camera,then the forces of the arcs were analyzed,and the influence factors on the arcs and metal transfer were found out. The results show that,when the current value I_m of the third arc M increases,the M arc shape bends downward obviously and promotes the metal transfer,the transition form is mixed transfer and short jet transfer. The main cause of spatter is that when the current switches,the droplets at the end of the wire do not fall into the pool,at the same time the electromagnetic force blows out the droplet transversely. I_m is set from 30 A to 38 A,the spatter is the least and the wire fuses stably.