In order to improve the surface wear resistance of titanium alloys, TC4 (Ti-6Al-4V) was selected as the matrix material, and diamond particles (20%, mass fraction) and CuTi alloy powder (10%, mass fractions) were added to Al-12Si filler metal. The diamond composite wear-resistant brazing coating on TC4 surface was prepared by induction brazing under argon protection. The effects of particle size of CuTi alloy, brazing temperature, and isothermal reaction time on the microstructure and wear resistance of composite coatings were studied. The results indicate that the composite coating is mainly composed of α-Al, Ti(Al1-xSix)3, CuAl2, and diamond particles. Reducing the particle size of CuTi alloy powder and increasing the brazing temperature can promote its full reaction with the brazing alloy. With the increase in temperature and insulation time, the CuAl2 phase at the grain boundary between α-Al and Ti(Al1-xSix)3 gradually disperses, improving the hardness of the brazing alloy coating. However, excessive insulation can cause the CuAl2 phase to start growing and to overlap with each other to form a coarse network structure, resulting in a significant increase in brittleness and a decrease in wear resistance of the brazed coating alloy.