Abstract: Additional electromagnetic field assisted welding has become a new technology in recent years. It can operate on the welding process by a non-contact way. The electromagnetic force can improve the performance of the weld, the production efficiency, and the crystallization of the microstructures by influences the low of molten pool, the arc shape and the transition behavior of molten droplet. In this paper, it was summarized that different scholas at home and abroad used different kinds of electromagnetic field to influence the fluid field of molten pool, the welding arc and the transition behavior of molten droplet, which mainly include the transverse magnetic field. the longitudinal magnetic field, and sharp angle magnetic field, and so on. But the physical process of are deposition forming under the action of electromagnetic is extremely complex, the physics mechanisms of heat, force and electromagnetic field in the welding process have not been completely analyzed the theoretical and numerical studies are urgently needed.