Abstract: The (AlN,TiN)-Al₂O₃ composites were fabricated by reaction sintering (Al,Ti)-Al₂O₃ powder mixtures with nitrogen at 750~800℃ and sintering 1420~1550℃ in nitrogen. The effect of powder contents and sintering process on mechanical properties, phases composites and microstructures of composites was researched by some methods such as XRD and SEM. The experimental results show that the formation of AlN and TiN aids to compact composites and increases their mechanical properties. Reaction sintering 20wt%(Al,Ti)-Al₂O₃ powder with nitrogen in 1520℃, 30MPa, holding 30min, could receive (AlN,TiN)-Al₂O₃ composites, which possess hardness HRA up to 94.1, bending strength 687MPa, and fracture toughness 6.5MPa·m^-1/2.