Power-supply is the “energy” of electronics for space payload. The design of the power-supply for an optic remote sensing equipment in GF-5 satellite is analyzed and researched, which includes design of protect circuit, inrush current limiting circuit, switch circuit, filter circuit, reliability design, et al. The results satisfy for the requirements of the relevant standards, and the target is designed on their own characteristics. The identification experiments and acceptance test were passed. The design with high-reliability and high engineering practical value is applied in space detection.