Abstract: A space laser communication terminal is characterized by a compact structure, a high degree of electronic integration, and high internal heat flux density, all of which pose strict requirements for its thermal control design. To satisfy the differentiated temperature requirements of multiple high-power devices and printed circuit board (PCB) chips, a comprehensive thermal control strategy combining differentiated heat dissipation paths, customized heat sinks, and a multi-level heat dissipation system was proposed. A finite element thermal model of the communication terminal and the satellite cabin was established to predict the temperature distributions of critical components under extreme thermal boundary conditions. Subsequently, a thermal vacuum test was conducted to validate the thermal design. The results showed that the maximum temperature deviation between the experimental and simulated results was 7.1%, well within the allowable engineering tolerance. In addition, the temperatures of all devices satisfy the specified thermal control requirements. These results demonstrate the effectiveness of the proposed thermal design and provide a reference for similar space electronic products.