The invention is applicable to the technical field of power grid planning, and provides an economic benefit evaluation method and device for a matched power grid after electric heating demand side management, and the method comprises the steps: obtaining an electric heating demand side management control strategy of a first region; according to the electric heating demand side management control strategy, calculating matched power grid investment, system construction cost, system operation cost and subsidy cost after the first area executes the electric heating demand side management control strategy, and taking the matched power grid investment, the system construction cost, the system operation cost and the subsidy cost as first investment funds; and taking the total invested fund of thematched power grid when the control strategy is not executed in the first region as a second invested fund, and calculating the economic benefit of the matched power grid after the control strategy is executed in the first region according to the first invested fund and the second invested fund. According to the method, the economic benefits of construction and reconstruction of the matched powergrid after demand side management can be conveniently calculated by obtaining the invested funds of the first area executing the electric heating demand side management control strategy and the invested funds before the control strategy is executed.