Because of its advantages,such as optimizing arc energy distribution, stirring the welding pool and easily regulating chemical composition,a new multi-stranded wire was employed to join in the welding of high nitrogen stainless steel structures and significantly reduced the porosity in the weld,and the precipitation of second phases in the weld was suppressed,the microstructure of the heat affected zone improved with relatively low heat input. The microstructure and mechanical properties were improved by analysing and optimizing the GMAW joints of high nitrogen stainless steel,meeting the engineering technical requirements of important welded structural parts.