Abstract: The boundary heat transfer coefficient of casting solidification process is an important boundary condition parameter and a key factor to determine the simulation accuracy of temperature field.In order to obtain the water-cooling heat transfer coefficient of copper/steel bimetallic sample, according to the inverse heat transfer method, through the measured temperature curve of water-cooling process, the water-cooling heat transfer coefficient was inversely calculated by ProCAST software. The results show that with the decrease of sample temperature, the water-cooling heat transfer coefficient first increases and then decreases, reaching a peak of 4980 W/(m²·℃) at 350℃.Compared with the simulation and the experiment under the same conditions, the simulation accuracy of the reverse heat exchange coefficient is high, accurately predicts the location of defects.After analyzing the temperature field, the process was improved, and the product defects were successfully eliminated by using the improved process.