Thermal energy storage is the main way to ensure solar power plant to generate electric in the form of stable and continuous. In this paper, a structure optimization model for large-scale, commercialization solar thermal energy storage system is proposed according to life cycle analysis. Based on the analysis of thermal energy storage medium, thermal energy storage tanks, insulation, bottom bearing structure, pump energy and land use, the optimization of thermal energy storage system is realized. Finally, the structure optimization design for 50MW solar power plant is implemented and storage tank’s geometric parameters are calculated. This research can provide technological support for large-scale application of solar thermal generation.