The invention relates to a power supply system for generating power by utilizing moon in-situ energy. The power supply system comprises a nuclear reaction power generation system, and the nuclear reaction power generation system comprises a nuclear reactor, an intermediate molten salt ring, a turbine, a high-speed motor, a gas compressor, a heat regenerator and a heat radiator. According to the power supply system, moon surface thorium-rich Kreep rock is collected and refined, so that in-situ utilization of energy is realized, and the transportation difficulty and cost of primary ore are greatly reduced; on the basis of maintaining the neutrons of the nuclear reactor not to escape, released gamma rays are subjected to photoelectric reaction to further generate electric energy, so that theworking efficiency of the nuclear reactor is further improved. The power generation scheme is based on closed helium circulation, and compared with traditional thermoelectric power generation, the advantages are that: the efficiency of power generation can reach 25-40%; internal circulation of a circulating working medium can be realized, no substance is exchanged with the outside, and the environmental adaptability is good; meanwhile, due to the rotary working characteristic, the energy density is high, and miniaturization is easy; based on the characteristics of large day and night temperature difference, vacuum and low-gravity environment on the surface of the moon, a power station energy storage mode taking a rotary flywheel as an energy storage link is provided.