The invention discloses an electric power adjusting method of a combined heat and power generation unit containing a heat storage tank. The adjusting method aims at solving the problem that the electric power adjustment is limited by the operation mode of the combined heat and power generation unit with the function of determining electricity by heat; the working characteristics of a combined heatand power generation system are changed by adding the heat storage tank, thus the coupling relation of determining electricity by heat in the past is solved to a certain extent, the load adjusting capacity of a power grid is improved, and the absorption capacity of the power grid on new energy such as wind power is facilitated. According to the electric power adjusting method, the contradiction that the peak load regulation capacity of the system is insufficient due to the fact that the input of the combined heat and power generation unit in the heat supply season extrudes the grid capacity of new energy such as wind power is solved. Therefore, the method has great significance.