Abstract: In the field of building energy conservation, solar energy is a highly favored clean energy source. However, the instability and discontinuity of solar energy greatly affect its application. Phase-change energy storage technology is widely used for solar energy storage because of its huge latent heat and constant temperature during phase change. To summarize the application effect and research status of phase-change energy storage technology in the field of solar energy storage, this paper reviews the research progress on solar energy storage tanks based on phase-change energy storage materials at home and abroad. This paper focuses on the research progress on phase-change material (PCM) packaging technology from the aspects of geometry packaging and microcapsule encapsulation. The improvements in material thermal conductivity, supercooling and phase separation problems, and material cycle durability are summarized and analyzed. Moreover, this paper summarizes and analyzes the existing research on the structural optimization design of solar thermal storage tanks, stratification of solar phase-change energy storage tanks, storage performance of solar phase-change energy storage tanks, operation strategy of solar phase-change energy storage systems, and performance improvement of the solar heating system by a phase-change energy storage tank. The advantages and disadvantages of solar energy storage tanks based on PCM energy storage in applications are summarized. Finally, the research idea of improving the performance of solar phase-change energy storage tanks is proposed. First, it is suggested that further research should be conducted on the encapsulation technology and heat transfer enhancement technology of composite PCMs, and the economic problems of PCM preparation should be fully considered. Second, the problem that PCM cannot completely melt or solidify during heat storage and release should be comprehensively studied to further improve the energy release performance of the heat storage tank. Third, the structural design and operation strategy of solar phase-change energy storage tanks should be optimized. Finally, to further explore the application potential of solar phase-change energy storage tanks, it is necessary to develop a multi-energy coupled heating system based on a solar phase-change energy storage tank, study the cascade utilization of various energy sources such as photothermal, photoelectric, and electromagnetic heat, and improve the stability and energy conversion efficiency of the multi-energy coupled heating system. This study aims to provide a reference for further research on and application of solar phase-change energy storage tanks.