Hybridizing solar energy with a coal-fired power plant has proven to be an efficient way of reducing coal consumption and discharged pollutants. In this study, solar energy was employed to heat boiler inlet feedwater through a solar high-pressure feedwater heater HO to increase its temperature. Solar-aided feedwater heating of a N600-24.2/566/566 supercritical coal-fired power plant is discussed as a case study. An all-condition mechanism model (ACMM) of SACFPP was proposed and simulated by MATLAB/Simulink. The maximum solar energy input for the safe operation of a boiler was determined as 66,544 kW based on ACMM simulation results. Moreover, the boiler efficiency and solar-to-electricity efficiency plummeted as solar energy input increased. The solar-to-electricity efficiency decreased from 23.33% to 20.33% when the solar energy input increased from 16,636 kW to 66,544 kW (in 100%THA). The solar-to-electricity efficiency decreased from 16.76% to 13.29% when the solar energy input increased from 16,636 kW to 66,544 kW (in 35%BMCR). A high unit load conesponds to high solar-to-electricity efficiency. SACFPP had a high coal saving rate when it operated in a lower load condition.