To solve the difficulty of selecting an appropriate heat sink for complex heat flows, the design of high-power heat sources for space cameras was investigated based on the design principle of reducing the total heat flow to a heat sink. First, the heat flow to a camera was analyzed according to a space environment. Subsequently, by analyzing the heat flow and working mode of the heat source, the efficiency of heat dissipation from the heat source and the area of the radiant cooling plates were reduced by installing radiant cooling plates on both sides of the camera and coupling them through heat pipes. Finally, the thermal analysis was verified using a thermal simulation software based on the camera’s space environment and the thermal control measures taken. The simulation results showed that the temperature of the visible focal plane component was -1.9℃ to 12.9℃, the temperature of the infrared camera circuit board was -1.7℃ to 6.7℃, the temperature of the hot end of the chiller was -12℃ to 0.3℃, and the temperature of the chiller compressor was -11.3℃ to 21.3℃. The temperature index requirements were satisfied, and the problem of heat dissipation from the high-power heat source of the camera under complex heat flow was solved.