Abstract: Laser gas nitriding process was used to fabricate the nitride layer with high hardness and wear resistance on the surface of TC4 titanium alloy. The changes of the macroscopic state of the samples’ surface after nitriding,the microstructure and the corrosion resistance of the nitriding layer were analyzed. The surface roughness of the sample increased after the laser gas nitriding. Compared with the self-corrosion potential of TC4 titanium alloy,the self-corrosion potential of nitriding layer positively shifted 0. 0424 V,which indicated that the corrosion resistance of the surface nitriding layer was enhanced.