Abstract: A parallel double-wire pulse MAG welding system has been developed, in which the two welding power sources were connected by the double-wire pulse controller.The current signals and voltage signals of the two arcs were collected.Synchronously high-speed photography system was used to observe the metal droplet transfer process and arc behavior.On the basis of a stable welding process, three factors, i.e.peak and base value of pulse voltage, the distance between the tips of the two wires in the vertical direction of the weld, inclination angle of the two welding torches were studied.Their influences on the arc behavior, metal droplet transfer and the formation and dimension of the weld were analyzed.The optimal peak and base value of pulse voltage was found out.The upper critical distance of the two arcs which could still form one weld pool and weld was 11 mm.It was found that the bigger the inclination angles of the torches, the deeper the penetration and the narrower the weld width, and also the higher the reinforcement of the weld at the same welding and wire feeding speed.