Abstract: Under carbon peaking and carbon neutrality goals, the demand for energy transition in China is increasingly urgent. Addressing the inherent challenges of solar energy, such as its discontinuous temporal distribution （day-night cycles） and uneven seasonal availability （summer-winter variations）, through advanced energy storage technologies is a critical bottleneck that needs to be overcome. This study proposes a solar thermal power generation system integrated with a CaO/Ca(OH)₂ thermochemical energy storage system for cross-seasonal energy storage. The system features a fast-response and technologically mature MgCl₂/KCl molten salt storage system for daily energy storage, coupled with a high-energy-density and low-loss CaO/Ca(OH)₂ thermochemical storage system for seasonal energy storage. By synergistically combining these two systems, the proposed solution enables “daytime energy for nighttime use” and “summer energy for winter use”, significantly improving the annual utilization efficiency of solar energy. A 100 MWe integrated solar power generation system with cross-seasonal energy storage was designed, comprising a tower-based solar concentrator subsystem, a molten salt storage subsystem, a calcium-based thermochemical storage subsystem, a supercritical CO₂ Brayton cycle power generation subsystem, and an organic Rankine cycle power generation subsystem. To accommodate varying daily and seasonal operational conditions, six system operation modes were proposed, including daytime and nighttime modes for summer, winter, and transitional seasons, along with corresponding control strategies. Dynamic performance simulations were conducted using hourly meteorological data from Lenghu Town, Qinghai Province, China. The results demonstrate that the system generates 187.01, 183.08, 178.42, and 180.14 GWh of electricity in spring, summer, autumn, and winter, respectively. The annual average values for system energy efficiency and solar power generation efficiency are 26.24% and 21.09%, respectively. Notably, under a summer-to-winter solar energy input ratio of 1.509 （indicating a seasonal fluctuation of 50.9%）, the power generation ratio remains at 1.016 （indicating a seasonal fluctuation of 1.6%）, significantly mitigating the fluctuations in electricity output caused by seasonal solar energy variability.