The three-dimensional model of the optical module was established, and fnite element simulation was carried out to reveal the temperature distribution of the device. The results show that the shield cage obstructs the heat convection of the chip and affects adversely the heat dissipation efficiency. The infrared camera was used to observe the chips working temperature distribution, thus the simulation results were verified. Based on the conclusions, an optimal design of optical module was proposed to improve the convection efficiency by modifying the structure of shield cage and the simulation results proved the feasibility of this method, providing practical significance for the design and optimization of optical module products.