Abstract: To reduce the sintering temperature and improve mechanical properties of ZrO₂-based ceramics, adding different contents of nanometer aluminum powder in ZrO₂, Al₂O₃/ZrO₂ composite ceramics was prepared by in situ reaction of Al₂O₃ dispersion strengthening ZrO₂ matrix phase at different microwave sintering temperatures. The influences of the nano-aluminum powders contents and sintering temperatures on the microstructure and mechanical properties of Al₂O₃/ZrO₂ composite ceramics were obtained By XRD phase analysis, SEM microstructure observation test, mechanical properties, and so on. The results show that the suitable binder remove temperature of ZrO₂ matrix composite ceramic is 400℃. The optimized microwave sintering temperature of pure ZrO₂ and Al₂O₃/ZrO₂ composite ceramics is 1 350℃ under the condition of the holding time of 30 min. Al₂O₃/ZrO₂ composite ceramics with the addition of 0.5 vol% nanometer aluminum powder has better comprehensive properties. The density, hardness, bending strength and fracture toughness of it are 98.56%, 14.92 GPa, 607.07 MPa, 15.09 MPa·m^1/2, respectively. Compare to pure ZrO₂, its bending strength and fracture toughness increased by 10.46% and 16.62%, respectively.