A thermal control system for space cameras was designed according to its space environments and structure characteristics. Firstly, the thermal design guidelines of space cameras were summarized, and the thermal environment of a space camera was analyzed. Then, the thermal design of the space camera was carried out. By utilizing the thermal capacitance of a satellite, the passive thermal control was used for thermal isolation and thermal transmission and the active thermal control was conducted to implement the temperature compensation. Finally, four extreme test conditions were designed and thermal balance tests were undertaken according to various work patterns and different thermal environments. The test results show that the temperature difference is 3 ℃ between the space camera and the fitting surface, which meets the system requirements for storage work conditions. Furthermore, the whole space camera temperatures are -3.1 ℃ and 45.7 ℃, the lens temperatures are -4.5 ℃ and 46.8 ℃ in the low temperature and high temperature work conditions, respectively, and they meet the thermal control system requirements. In conclusions, the thermal design of the space camera is feasible and reasonable.