Abstract: The non-transfer metallic plasma torch and graphitic transfer injectors are used in producing nitrogen bearing stainless steel. Mixed nitrogen-argon-oxygen gas is adopted as plasma gas and alloying elements. It has been concluded that it is possible to smelt Cr-Mn-Ni steel with reproduceable nitrogen content of 0.15% to 0.3% in 30 min.The thermodynamic and kinetic conditions which affect nitrogen alloying of liquid steel are strdied,and the chemical and electric absorption phenomena are also investigated.The process conditions of strengthening diffusion and convection mass transfer are proposed to accelerate nitrogen absorption and increase nitrogen content of liquid steel.