This method means that the adjustment range is too smaller or too bigger than the original air volume or coal feed amount, in order to decrease or increase the combustion portion. This adjustment method usually is applied to the combustion conditions with bigger fluctuation, such as when coal feeding to the boiler is interrupted, and we increase the coal feeding amount of the other two coal feeders by a wide margin, and the increased coal feed shall be more than the coal feed before interrupting in order to make up the insufficiency of combustion share and to ensure the boiler output is not affected. Then according to the judgment from other parameters, adjust the air flow or coal feed rate to the original value in order to keep the stability of combustion. During suddenly load shedding, the adjusting method is on the contrary.