Abstract: The quenching factor analysis(QFA) method based on precipitation kinetics of aluminum alloy is combined with the finite element analysis method (FEM) to calculate the quenching sensitivity factor for the spray quenching process of 7050 aluminum alloy thick plate; and then the hardness of end-quenched sample was simulated, the effects of the plate thickness and the spray pressure on quenched hardness were analyzed. At last, the simulation results are verified by end quenching experiment. The results show that the decrease of spray pressure will cause loss of hardness, and the influence of water pressure decreases with the increase of plate thickness. The quenching effect of thin plate(thickness of 50 mm) is closely related to the spray pressure, when the spray pressure reduced from 500 kPa to 10 kPa, the core hardness decreased by 1.8%. The quenching effect of thick plate with thickness more than 100 mm is limited related to the spray pressure, when the spray pressure reduced from 500 kPa to 10 kPa, the decrease of core hardness was lower than 0.5%.