Power electronic technology has been widely used in today's society, and has played an irreplaceable role in improving the development and living standard. With the rapid development of China's space engineering, power electronic technology in the switching power supply applications also promote the spacecraft to miniaturization and high-power development. High frequency, modular, intelligent, energy-saving, and so must be included, including space power, switching power supply, including the future direction of application. Believe that the future, power electronics in the switching power supply applications will be further breakthroughs, the need to further strengthen its research. Based on this paper, the application of power electronics technology in switching power supply is analyzed.