Abstract: Aiming at a heat-supply unit integrated system with energy storage device, the method of using energy storage device to improve the operation flexibility of the unit was studied. Based on the coupling principle of coal-fired units and energy storage devices, two energy storage schemes of steam extraction were proposed. The thermodynamic models of coal-fired units and energy storage devices were built by using EBSILON thermal calculation software, and the effects of these schemes on system economy were analyzed. The results showed that the economy of two-stage mixed extraction scheme was better than that of only one-stage extraction scheme in the energy storage process, and the heat consumption of the unit could be reduced by 40 kJ/kWh; under the same operating conditions, the economy of the system would be reduced by increasing the heat storage and extraction capacity.