Nano-AlN and submicron-Al₂O₃ particles were simultaneously utilized in a 6061 Al matrix composite to improve the high-temperature strength. According to the SEM and TEM characterization, nano-AlN and submicron- Al₂O₃ particles are uniformly distributed in the Al matrix. Brinell hardness results indicate that different from the traditional 6061 Al matrix alloy, the aging kinetics of the composite is obviously accelerated by the reinforcement particles. The T6-treated composite exhibits excellent tensile properties at both room temperature and elevated temperature. Especially at 350 °C, the T6-treated composite not only has a high yield strength of 121 MPa and ultimate tensile strength of 128 MPa, but also exhibits a large elongation of 11.6%. Different strengthening mechanisms of nano-AlN and submicron-Al₂O₃ particles were also discussed in detail.