Abstract: Each system of Coal-fired power plant is coupled with each other, and the change of operating parameters has an impact on boiler efficiency, cold source loss and auxiliary power. In order to comprehensively evaluate the influence of operating parameters on the energy consumption level of Coal-fired power plant, this paper establishes the quantitative relationship between single variable and unit energy consumption level according to unit performance test, and calculates the energy consumption level of each system through the real-time data of SIS system. The results show that when the air cooling fan is at 45Hz, the comprehensive energy consumption of fan power consumption and unit vacuum is the lowest, and the air cooling fan has the optimum frequency. The comprehensive evaluation method can effectively guide the operation of Coal-fired power plant, and has a certain reference significance for the energy conservation and consumption reduction of similar units.