Abstract: Driven by the "Carbon Peak and Carbon Neutrality" strategy, the share of installed renewable energy capacity continues to rise, making large-scale energy storage a critical cornerstone for sustaining the stable operation of modern power systems. Focusing on three representative technologies—underground compressed air energy storage, underground hydrogen storage, and underground thermal energy storage— this study systematically reviews typical engineering projects and recent research advances worldwide, and analyzes their fundamental principles, engineering maturity, applicable geological conditions, and major engineering challenges. The results indicate that, owing to an insufficient understanding of thermo-hydro-mechanical-chemical-biological coupling mechanisms, the geological adaptability assessment framework for large-scale underground long-duration energy storage remains underdeveloped. Long-term wellbore integrity faces severe challenges under high-frequency cyclic loading and complex corrosive environments, while the accuracy of storage-reservoir state monitoring remains limited and intelligent control capabilities are still inadequate. In addition, the distinctive geological conditions in China, including the prevalence of thin interbeds in bedded salt formations and strong heterogeneity in deep saline aquifers, further increase engineering uncertainties. Accordingly, future research should shift from static mechanical assessment toward dynamic multiphysics-coupled evaluation; develop key materials and large-diameter wellbore equipment capable of withstanding high-temperature, high-pressure cyclic loading; establish intelligent operation and maintenance systems integrating multi-source monitoring with digital twins; and promote industrial cluster development through multi-energy complementarity among wind, solar, hydrogen, and thermal energy storage, together with the restructuring of value across the entire life cycle. These efforts can provide a scientific basis for the planning, safe construction, and long-term operation of large-scale deep underground long-duration energy storage in China, thereby contributing to the rapid development of China’s trillion-yuan green energy industry.