Abstract: Al2O3/diopside composites were fabricated by hot-pressing sintering process.Microstructure of the composites was analysed and mechanical properties such as fracture toughness,hardness and bending strength of the composites were tested.The bending strength and fracture toughness of alumina matrix ceramic composites sintered at 1 450 ℃,under 28 MPa for 30 min,are significantly improved and reache their maximums value of 4425 MPa and 4.76 MPa·m1/2,respectively.