TiN-Al₂O₃ composite powders with different TiN contents (0, 10%, 20%, 30% and 40% in volume) were prepared with micrometer TiN and α-Al₂O₃ powder (their purities were 99%) as starting materials by wet ball milling for 5 h. TiN-Al₂O₃ composite were then prepared by pressing the above composite powers, drying at 200 ℃ for 12 h and firing at 1 800 ℃ for 3 h in nitrogen atmosphere in hot-pressing furnace. The influences of TiN content on the mechanical properties and electrical conductivity of TiN-Al₂O₃ composites were studied. The results showed that the mechanical properties of the composite increased with TiN content increasing, while the resistivity of composites decreased. A composite with 40% TiN had 498 MPa bending strength, 4.285MPa·m^1/2 fracture toughness, 1.34×10^-3Ω·cm resistivity. The SEM analysis showed that the fine TiN crystals distributed among the crystal boundary of Al₂O₃ matrix. They bonded together forming a net-like structure which played a role of restraining Al₂O₃ grains from growing up, and toughening and strengthening, so the mechanical properties of TiN-Al₂O₃ composite were enhanced.