BS960E bainite high strength steel is selected for new heavy duty vehicle. The excellent MAG welding procedure of BS960E bainite high strength steel is obtained by means of optimizing welding groove and controlling current and voltage. On this basis,the dynamic and static characteristics of MAG welding power supply and the droplet transfer behavior are further explored by using high speed photography and online welding monitoring technology,and the metallographic structure of the welded joint is analyzed. The results show that the welding current is stable and welding voltage is low under the optimal procedure conditions,and the metal transfer mode presents one droplet per pulse. The microstructure of the joint is mainly tempered martensite,acicular ferrite and granular bainite,which makes the hardness of the weld higher than that of the base metal.