Abstract: In order to get the optimal parameters of units which adopted different cooling characteristics in different operating points and determine the operating ways of constant pressure\|sliding pressure\|constant pressure, units coal consumption was calculated and standard coal consumption and coal consumption curve were fitted by using Matlab.Then the units coal consumption curves and the differential curves could be reached under the condition of equal slight addition. The results showed that water\|cooled units, which slight incremental coal consumption rate was low, raised the load firstly, then air\|cooled units, which slight incremental coal consumption rate was high, raised the load lately;the unit adopted operating way of constant pressure when its load was higher than 80% or less than 40% rated load and it adopted operating way of sliding pressure when its load was between 40％ and 80％ rated load.