Abstract: Under the background of low-carbon energy transition, the inherent intermittency and volatility of wind and photovoltaic power pose significant challenges to grid integration and utilization efficiency, which have become a key bottleneck constraining the optimization and upgrading of the energy structure. Energy storage technology, as a core means of achieving inter-temporal energy regulation, provides crucial technical support to address this challenge. As an emerging long-duration, large-scale energy storage technology, deep geothermal energy storage has gradually become a research focus and frontier directions in the field of renewable energy, owing to its prominentqianyan advantages such as substantial scalability, favorable economics, wide application scenarios, and strong system resilience. This paper systematically elaborates on the technological background and core strengths of deep geothermal energy storage, and conducts an in-depth analysis of the classification characteristics of deep geothermal systems, the geological structures for energy storage, as well as the key factors influencing storage capacity and efficiency. It provides a detailed review of mainstream technical pathways, including hydrothermal reservoir heat storage, geotechnical energy storage, compressed air energy storage, and CO₂ plume geothermal systems, covering their working principles, current status of engineering applications, and key technological advances. The paper comprehensively examines the critical issues currently faced by deep geothermal energy storage in areas such as site exploration, efficiency regulation, and environmental safety risk prevention. Finally, future development recommendations are proposed from two dimensions: the construction of a multi-energy complementary energy system, and the enhancement of technological innovation and industrial development systems. The aim is to provide theoretical reference and technical support for the large⁃scale application and sustainable development of deep geothermal energy storage technology, thereby contributing to the achievement of China’s“dual-carbon”goals and energy security strategy.