Abstract: The effects of heat transfer coefficient and quenching modes on the temperature field of a steel plate during quenching on a roller quenching machine were analyzed by a heat transfer control equation derived. The results showed that if the heat transfer coefficient increases within a certain range, the boundary conditions of convective heat transfer affect the surface and internal temperature of a plate of certain thickness significantly in its quenching process. It was found that the roller quenching machine has such characteristics that the steel plate is cooled in a high-pressure quenching zone where the cooling intensity is so high that the temperature gradient can be kept great inside the plate to ensure its high cooling rate, then the plate is fully quenched in the low-pressure quenching zone with lower cooling rate, thus decreasing the temperature gradient in the plate with its internal thermal stress reduced.