Based on the size, material properties and working conditions of the rubber cylinder, a reasonable assumption was put forward for the heating process of the rubber(EVA) (EEthylene, VAVinyl Acetate), and a simplified heat transfer mathematical model of rubber temperature was established in this paper. With help of the finite element method(FEM) and ANSYS 14.5 simulation software, a 3D finite element model of the heating temperature field of rubber cylinder was set up. As an example, the temperature field of the integrated rubber cylinder was calculated, and the temperature field distributions of the rubber and the melt rubber volumes at all time points were gained, else the accuracy of the simulation results was verified by experiments. Due to the heating time of the original model is too long, resulting in low working efficiency and carbonization of the rubber. So the structure of the rubber cylinder need to be modified, and the simulation result of the improved model was gained. The feasibility of model modification was verified by comparing the results of the original model and the improved model, and the reference and guidance for the improvement of the actual model were provided.