Objective In order to enhance the surface properties of titanium alloy (TC4) blade and solve the failure problem. Methods With laser gas nitriding technology instead of traditional nitriding technology, TiN surface modification layer was prepared on the surface of titanium alloy (TC4) with a 2 kW flexible fiber coupled diode laser. The wear-resistant property and anti-cavitation property of the nitriding layer and the substrate (TC4) were examined by the friction-abrasion testing machine and modified experimental device for cavitation erosion. Results The results showed that the wear loss weight of TC4 substrate was 20.2 mg while that of nitriding layer was 2.3 mg, which was only 11.3% of TC4 substrate. The wear resistance increased by 7 times compared with that of the TC4 substrate. The cavitation erosion loss weight of TC4 substrate was 4.08 mg while that of nitriding layer was 1.13 mg. The anti-cavitation property increased by 2.61 times compared with that of the TC4 substrate. Conclusion A large number of TiN dendrites in the nitride layer can be obtained with diode laser by laser gas nitriding titanium alloy blade, which improves wear-resistant property of the surface. The distribution of the basket shaped structure of TiN dendritic crystal improves the anti-cavitation property of the surface.