Abstract: As the spacecraft operates in a low-temperature environment in deep space. the low-temperature performance ofthe spacecraft DC/DC converter is a very important issue. This paper discusses the configuration of the DC/DC converter of the spacecraft, its key components, and the low-temperature performance of the power semiconductor (power MOS and power diode) and the PWM control chip. The experimental data for the 25W/5. 8V DC/DC converter of a spacecraft during. 35~80℃ are analyzed. These analyses provide some guidance for the future deep space exploration.