The invention discloses a correction method for the fuel quantity of a supercritical once-through boiler during the change of feed water temperature. The correction method has the characteristics by comprising the links of inputting of basic parameters and operation and structure parameters, calculation of hot air temperature at an air preheater outlet after the change of the feed water temperature, and calculation of water temperature at an economizer outlet and heat balance of a hearth after the change of the feed water temperature. The basic parameters and the operation and structure parameters of the boiler are input, the deviation of feed water temperature of the supercritical once-through boiler is given, and the hot air temperature at the air preheater outlet after the change of thefeed water temperature is determined according to a differential deviation method. The water temperature of the economizer outlet after the change of the feed water temperature is determined. The fuel quantity after the change of the feed water temperature is determined through heat balance of the hearth, and the whole calculation process is conducted through an iterative calculation method. Quantitative precise instructions can be achieved for the fuel quantity after the change of the feed water temperature of the supercritical once-through boiler, and the effect of precise adjustment of thefuel quantity according to the coal-water ratio after the change of the feed water temperature of the supercritical once-through boiler is achieved.