The Ti-6Al-4V titanium alloy was treated with micro-arc oxidation by adding HfO2 into the electrolyte. The effect of adding HfO2 on the characteristics of the micro-arc oxidation film of titanium alloy was studied by characterizing the surface and cross-section morphology of the micro-arc oxidation film, the composition of the film and the electrochemical behavior, and measuring the thickness, hardness, roughness and other parameters of the film. The results show that after adding HfO2, the main components of the micro-arc oxidation film are Al2TiO5,TiO2 and γ-Al2O3.The appropriate concentration of HfO2 can promote the film-forming reaction, improve the microstructure of the micro-arc oxidation film, improve the thickness and hardness of the film and reduce the surface roughness. The film sample has a double-layer film structure, and the corrosion resistance of the film sample is better than the original substrate. When the concentration of HfO2 is 3.0g/L, the comprehensive performance of the micro-arc oxidation coating is the best.