Abstract: The change in temperature during plate cooling was investigated by numerical simulation to analyze how the cooling rate changes with heat transfer coefficient. The results showed that the change of cooling rate with increasing heat transfer coefficient presents an S-like curve, and then the cooling rate becomes stable gradually. With the increasing of heat transfer, when the temperature of plate surface approximates to that of cooling water at finish cooling and the ultimate cooling rate comes true. The ultimate cooling rate is far higher than the cooling rates of both accelerated cooling(ACC) and ultra fast cooling(UFC), and it decreases with the increase in plate thickness and start cooling temperature and decrease in finish cooling temperature. However the cooling water temperature has less influence on the ultimate cooling rate.