Abstract: Commercial software AVL-FIRE was used to simulate and experiment the immersion quenching process of steel cylinder. The quenched workpiece was a steel cylinder and water was used as quenching medium. Based on the principle of equal heat flux between quenched working fluid and workpiece surface, the temperature field of workpiece was solved by ACCI method. The thermal property parameters of the workpiece were set to the parameters related to the temperature change by polynomial fitting method, and the simulation results were compared with the numerical simulation results with the thermal property constant. The results show that the numerical simulation results of the thermal properties of the workpiece with temperature change are in good agreement with the experimental data and are closer to the actual experimental data. The simulated temperature field can be used for thermal stress analysis and guide the actual production.