Eco-environmental concerns, such as water supply and demand imbalance, water pollution, have been increasingly prominent with the rapid urbanization and climate change. Water conservation/storage in catchments affects the ecosystem functions of hydrological regulation and water purification. A deep understanding of the process and capacity of water storage is the basis for managing the above-mentioned eco-environmental concerns. With the development of isotope hydrology, the superiority of isotope technology in the study of hydrology and water resources has gradually become prominent. Hydrogen and oxygen isotopes are inherent properties of water and play an important role in studies such as water traceability and water residence time estimation. However, most related studies only paid attention to a certain aspect of the hydrological process, remaining absence of a clear research framework of water conservation. To promote the applications of hydrogen and oxygen isotopes in water-storage related studies, this study summarizes the researches on the application of hydrogen and oxygen isotope to characterize the process, ability, and effects of water storage. The research framework and direction of water storage using hydrogen and oxygen isotope is summarized in terms of the process, capacity, and the effects of water conservation/storage. The study has important theoretical and practical meaning for understanding the water conservation/storage mechanism of the basin and assessing the value of water conservation/storage services.