Abstract: Abstract With the development of clean energy, the demand for flexibility and peak shaving ability in power systems continues to increase. Molten salt heat storage is a high-density energy storage technology that uses latent heat of phase change and high specific heat capacity for heat storage, which can provide effective peak shaving support for power grids. This paper takes a 300,000 unit as an example to evaluate the challenges and future development prospects faced by molten salt heat storage in peak shaving and transformation of thermal power units. The research shows that the current project capital base financial internal rate of return of a molten salt heat storage project can reach 14.82%, which has great economic advantages and development potential, and is worthy of promotion and application.