Abstract: Aiming at the difficulty of thermal pad selection and complex cooling block designs, an efficient design and repair method for cooling blocks in the thermal design of spaceborne electronic devices is proposed in this paper, taking a spaceborne data processor as an example. The thermal pad selection and cooling block structural design scheme are determined by analyzing the relationship between the thermal pad thickness and thermal contact resistance as well as the relationship between the thermal pad compression and contact pressure. The rationality of the thermal design is verified through thermal simulation analysis. Through trial installation validation with thermal pads, it is verified that after the secondary repair of over 180 cooling blocks in the equipment, the matching of installing 0.5 mm GapPad3000S30 thermal pads is ensured. This verifies the suitability and efficiency of the cooling block design and repair method. This method has significant engineering practical value in the development of spaceborne electronic devices with high heat consumption and multiple heat-dissipating components.