Abstract: As a critical strategic resource, helium is mainly extracted from helium-rich natural gas. Therefore, the enrichment and accumulation mechanism of helium in gas reservoirs has become a current research focus. Based on the exploration practices of typical helium-rich gas reservoirs at home and abroad and previous research results, this study systematically summarizes the genesis, source, and enrichment-accumulation process of helium, aiming to provide comprehensive cognition of enrichment conditions and laws for helium exploration and research personnel. Studies have shown that helium in helium-rich gas reservoirs is mainly crust-derived, primarily originating from the α-decay of uranium （U） and thorium （Th） in rocks. Although all types of rocks contain U and Th and can generate helium, the hydrocarbon generation intensity is much higher than the helium generation intensity. The generated hydrocarbon gases will strongly dilute helium, only forming low-helium gas reservoirs with a low contribution ratio of reservoirs. In contrast, the ancient basement dominated by granite has become the main helium source for helium-rich gas reservoirs due to its high U and Th contents and long geological age. After helium generated by U and Th in source rocks breaks through the sealing effect of minerals on helium, it will migrate to reservoirs in the form of free gas together with natural gas, and then capture helium generated by U and Th in reservoirs, eventually forming low-helium gas reservoirs. Only a small number of gas reservoirs have the opportunity to be supplemented by helium generated by U and Th in the ancient basement, thus forming helium-rich gas reservoirs. In addition, helium and nitrogen show a significant positive correlation and coupled enrichment relationship in gas reservoirs. They share the same source （ancient basement）, the same migration carrier （groundwater）, and the same enrichment process. Helium in the ancient basement migrates to gas reservoirs in the form of water-soluble gas and is released through degasification under the condition of decreasing temperature and pressure. Based on this, helium-rich resource exploration should prioritize natural gas areas close to the ancient basement and with conditions for the formation and release of water-soluble helium. The results of this study provide theoretical support for further research on helium enrichment mechanism and scientific basis for helium resource exploration target selection and evaluation.