Abstract: Research on droplet transfer of swing arc narrow gap welding is the base for understanding this novel process deeply. The process of metal transfer in swing arc narrow gap welding is more complex than that in normal welding process. In this paper, the high-speed camera and welding electrical signal collection system were applied to observe the metal transfer process. The droplet transfer characteristics and the influence of parameters on droplet transfer in swing arc narrow GMAW were analyzed. The arc swing in the narrow gap groove causes the regular change of arc length and welding current due to the change of distance between the wire and the sidewall, and finally the droplet transfer in swing arc narrow gap changes regularly.