Abstract: 2Cr13 martensitic stainless steel was treated by plasma source nitriding at 450℃ for 6 h, and then the microstructure, phase composition, wear resistance and corrosion resistance of the steel surface layer before and after nitriding were studied and compared. The results show that after nitriding, an about 18 μm thick compound layer composed of α_N, ε-Fe₃N and γ'-Fe₄N and a nitrogen diffusion layer with obvious refined structure were formed on surface of the stainless steel. The nitrogen atom penetration depth reached 20 μm. The surface hardness of the nitrided stainless steel was up to 1 350 HV and the friction factor was lower than that before nitriding. The wear mechanism changed from adhesive wear before nitriding to oxidative wear after nitriding. The wear resistance after nitriding was obviously higher than that before nitriding. In 3.5wt% NaCl solution, the anodic polarization curve of the stainless steel before nitriding only showed a feature of activation dissolution while after nitriding showed features of activation dissolution, self-passivation and pitting breakdown. After nitriding, the free-corrosion potential increased to -104 mV and the corrosion resistance was improved significantly.