Abstract: To establish a heat transfer model for a certain satellite circuit board, the temperature field during preliminary thermal design is studied, and the optimization design for heat dissipation problem of high-power overheated components on the printed circuit board is carried out. ANSYS software is used to simulate the temperature field of the circuit board during operation. Based on the theory of thermal resistance, a passive thermal control optimization design scheme is adopted, which uses welded thermal conductive copper bars to directly connect the box to achieve thermal conductivity and reduce component temperature. By analyzing the temperature changes of high-power devices before and after optimization, it is found that setting up thermal conductive copper bars can effectively reduce the temperature of the components. The research result shows that in the design of satellite circuit boards, passive thermal control optimization is carried out through ANSYS simulation combined with thermal resistance theory. The method of connecting the box with thermal conductive copper bar has significant effects on solving the heat dissipation problem of high-power overheated components, providing effective reference for the thermal design of satellite circuit boards. Further research can be conducted on the applicability and optimization space of this method under different working conditions and component layouts.