With the continuous development of space technology, the assembly density of electronic components on the spaceborne remote sensing controller printed circuit board (PCB) is becoming higher and higher. And too much high-power electronic components working efficiently will be bound to produce more heat than their own limitation, only relying on the metal boss at the top of the electronic components to contact the cooling mode cannot timely export the working heat of the components, resulting in the damage of the components, so it is necessary to conduct heat efficiently. This paper focuses on the electronic components with high power consumption and high heat which are densely packed on the remote sensing controller board in high orbit, proposed an efficient heat dissipation method. By making use of the limited heat dissipation surface of the components to contact the heat conduction at the bottom and top of the components, the high heat generated by its work can be exported in time to ensure its stable operation. Finite element simulation is conducted to compare the influence between the method of this paper and the traditional thermal conductivity method on the heat dissipation function of components. According to the comparison results, the thermal conductivity method proposed in this paper is suitable for the thermal conductivity design of the spaceborne controller PCB board with too many high-power electronic components, and the rationality of this design is verified by thermal test. The results provide some guidance for the thermal conductivity design of high-power controllers with complex functions.