Abstract: To enhance the peak-shaving capability of coal-fired units, a molten salt thermal energy storage assisted peak regulation scheme for coal-fired units based on flue gas and steam is proposed. In this scheme, flue gas and main steam are extracted to heat molten salt together, and two molten salts with different parameters (solar salt and Hitec salt) are used for thermal energy storage. This integrated scheme addresses the limitation of narrow operating temperature range for single molten salt, and further improves the operational flexibility of coal-fired units. A thermodynamic model of the proposed scheme is established, and the system performance is analyzed from both thermodynamic and economic perspectives. The results indicate that the scheme can expand the operating range of coal-fired units to 20.00%THA–107.71%THA. The equivalent round-trip efficiency of the system reaches 77.06%, and the exergy efficiency is 38.32%. The total investment cost of the scheme is 309.4798 million yuan, with a dynamic payback period of 4.35 years and a net present value of 852.8383 million yuan. This study can provide theoretical support and feasible solutions for the design of molten salt thermal energy storage systems and the flexible peak regulation retrofitting of coal-fired units.