Abstract: The residual stress seriously shortens the service life of part during its service. The temperature distribution and residual stress distribution of an engine ZL205A alloy workpiece under different quenching medium temperatures were studied by ABAQUS software simulation and experimental testing, and the distribution and evolution of residual stress during quenching heat treatment were studied. Among them, the solution temperature was 540 ℃, and the water-cooled quenching temperature was set to 25 ℃, 50℃ and 80 ℃, respectively. The simulation results show that with the increase of quenching medium temperature, the residual stress of the workpiece decreases significantly, and the compressive stress occurs in the position with fast cooling rate, and the tensile stress occurs in the position with slow cooling rate. The blind hole detection method was used to measure the residual stress of the feature position, and it was compared with the simulation results, the validity and accuracy of the simulation results were verified. Therefore, under the premise of ensuring the mechanical properties of ZL205A aluminum alloy, it is recommended to adopt 80 ℃ quenching process.