The present disclosure provides a low-energy-consumption in-situ extraction system for lunar rare gas and an extraction method. The system includes a screening device, a grinding device and a heating device. The method includes: a. using a robot arm to collect lunar soil and put into the screening device, and screening lunar soil with a particle size below 100 μm; b. adding and grinding screened lunar soil in the grinding device; c. adding and heating ground lunar soil in the heating device to 150-250° C., and releasing rare gases adsorbed. The present disclosure uses screening, grinding combined with traditional heating methods to achieve low power consumption in extracting rare gases on the surface of the moon, and extraction power consumption is only 10-30% of the power consumption of hot-melt extraction at 900° C. in the prior art, which is beneficial to promote the lunar resource utilization.