With a large scale of renewable energy was incorporated into the power system and combined heat and power plant “determining power by heat” operation, results in the deficiency of peak load dispatching power system. This paper proposes the configuration of electric heat storage equipment in large heat-supply power plant and the use of thermal inertia of the heating system to improve the unit peaking capacity. The first step is to expand the feasible region in which the combined heat and power plant can operate by deploying electric heat storage equipment; Secondly, the resistance ability of thermal inertia to power fluctuations and the delayed response characteristics are analyzed, and the inertial power flow model of thermal network is constructed; Finally, a bidirectional optimization control strategy is proposed with the objective of minimum standard deviation of the load curve after peak regulation.