TC4 titanium alloy was treated by microarc oxidation (MAO) with Si₃N₄ nanoparticles into the base electrolyte. The effect of the Si₃N₄ content on the surface morphology, corrosion resistance, and wear resistance of the coatings was studied. The results show that MAO coatings with Si₃N₄ addition present the porous structure, and the coating is the thickest as the Si₃N₄ content is 1 g/L. The coating with the addition of 1 g/L Si₃N₄ after acid corrosion test for 7 d shows excellent corrosion resistance with the lowest corrosion rate of about 0.057 mg·cm^-2·d^-1. With the addition of Si₃N₄, the antibacterial property of MAO coatings is firstly increased and then decreased, which is optimal when the Si₃N₄ addition is 1 g/L. The Si₃N₄ addition can obviously enhance the wear resistance of the coatings in the simulated seawater. When the Si₃N₄ addition is 3 and 4 g/L, the friction coefficient of MAO coatings is low and stable. In addition, MAO coating with the addition of 3 g/L Si₃N₄ shows the excellent wear resistance.