Abstract: Al-10Si-4Cu-0.7Mg alloy was prepared at 500 ℃×5 h solid solution+different time cryogenic+170 ℃×8 h aging treatment.The effects of different heat treatment processes on the microstructure and mechanical properties of Al-10Si-4Cu-0.7Mg alloy were studied by SEM, tensile test, hardness test and friction and wear test.The results show that the tensile strength and hardness of Al-10Si-4Cu-0.7Mg alloy in solution+10 h cryogenic+aging state are 358 MPa and 158 HV, respectively, which are 17.4% and 27.4% higher than that of T6 state alloy respectively.In addition, the wear resistance of Al-10Si-4Cu-0.7Mg alloy under high and low load is also higher some extent than that of T6 state alloy.Compared with T6 state Al-10Si-4Cu-0.7Mg alloy, the amount of Si phase in the alloy of solid solution+10 h cryogenic+aging state is obviously increased, which is more fine and uniform, and the undissolved second phase is also obviously refined.