The rotor engine is of uneven temperature distribution inside the cylinder block during its working process, which would cause thermal stress, thermal fatigue and other problems, affecting service life of the engine. To improve safety of the rotor engine during operation, extend its service life and address the main issue of high temperature in the high-temperature region, three optimization methods including lengthening fins, grid structure, and copper–aluminum integration are proposed based on the theory of heat transfer of the rotor engine. Based on the premise of verifying the simulation correctness, the heat exchange processes of different models are simulated using Fluent. The simulation results show that the proposed three schemes can improve heat dissipation performance of the rotor engine. Compared with the unoptimized model, surface area of the lengthened-fin model increased by 124.4%, heat dissipation capacity increased by 4.9%, these of the grid-structure model increased by 158.5% and 8.3%, respectively. As for the copper–aluminum integration model, with the synergistic effect of structure and material, has an increase of 15.2% in the heat dissipation capacity. The experiment demonstrates that rational optimization of fin structure and material can improve heat dissipation capability of the rotor engine.