Abstract: To address the issue of severely limited operational flexibility caused by the strong thermal-electric coupling characteristics of combined heat and power units, this paper proposes a molten salt thermal energy storage system integrated with a steam ejector. Taking a 350 MW heating unit as the case study, a thermodynamic system model and a mathematical model of the steam ejector were established using EBSILON software. The impact of integrating the molten salt thermal energy storage system on the unit's thermodynamic performance was analyzed from the perspectives of energy balance and exergy balance. Results show that when the molten salt steam supply ratio γ equals 1, the downward peak shaving capacity reaches 34.13 MW, while the upward peak shaving capacity reaches 40.97 MW. The overall thermal efficiency and exergy efficiency slightly decrease to 60.06% and 38.49%, respectively. Overall, the unit achieves optimal thermodynamic performance when the molten salt steam supply ratio is maximized.