As the casting film is very thin (micron scale), if the 1∶1 geometric model is used to simulate the heat transfer of thin film, the number of grids will reach 10 billion level, and the simulation calculation will become very difficult. Therefore, this paper proposed a heat transfer simulation model of thin film thickening. In other words, the geometric model of film is enlarged, while the geometric model of roller and cooling water pipe remains unchanged, which can successfully realize the heat transfer simulation of the film cooling process. The study show that the temperature field on the surface of the film and the roller presents a spiral distribution, namely,“channel trace”, which is consistent with the thermal imaging test results. At the position with spiral guide vane, the surface temperature of the film and roller is high, the temperature of the corresponding position of the cooling water channel is low, and the film temperature fluctuates up and down in the axial direction of the film, with an amplitude of less than±1℃. The cooling process of casting film on the tape casting roller can be divided into two stages:temperature quenching stage and temperature stable stage. The cooling of the film mainly occurs in the quenching stage, and the quenching time is 0.03s, during which the film temperature can rapidly dropped to less than 40℃ from 220℃. The increase of the cooling water velocity in the spiral channel has little influence on the temperature change of the film in the circumferential direction, but has great influence on the average temperature rise slope of the film in the axial direction. The relationship between the flow velocity of cooling water in the spiral channel of tape casting roller and the slope of film axial temperature rise given at the end of this paper can provide technical reference for the design of flow rate of casting roller.