Abstract: To enhance the hardness of ZrO₂ matrix composites, TiC_0.7N_0.3/ZrO₂ composites were fabricated by hot pressing method, and the effects of TiC_0.7N_0.3 particle reinforcing phase on the phase composition, microstructure and mechanical properties of the composites were investigated. The results show that the addition of TiC_0.7N_0.3 has the effect to stabilize tetragonal ZrO₂ (t-ZrO₂), and can improve the t-ZrO₂ content in TiC_0.7N_0.3/ZrO₂ composites, thus improve the fracture toughness. With the hot pressing temperature and TiC_0.7N_0.3 content increasing, the hardness of composites increases. When hot pressing at 1 400 ℃, TiC_0.7N_0.3 decomposes partially, and the released N can react with reduced ZrO₂ to form ZrN, which increases the hardness of composites. The relative density of 35wt% TiC_0.7N_0.3/ZrO₂ composites after hot pressing at 1 400 ℃ exceeds 99.9% and Vickers hardness reaches 17 GPa. While the fracture toughness of composites is higher after hot pressing at 1 300 ℃, which is 6.48 MPa·m^1/2. The conclusions provide references for microstructure controlling and improvement TiC_0.7N_0.3/ZrO₂ composite properties.