Abstract: Abstract: With the increase of energy demand, the coal into the furnace of the coal-fired power unit deviates from the design of coal, and even mixed with low quality coal, coal slime and sludge, the boiler deviates from the design condition, the need for a comprehensive check of the boiler calculation, in order to ensure the safety of the boiler, at the same time, the unit to complete the task of peak adjustment, heating, power generation.Because of deviating from the design value of coal, need to focus on the coal pulverizing system, boiler low-load stable-combustion value calculation and experiment, this article under the boiler manufacturer calculation data, according to the boiling coal deviation data back to the outlet temperature of the coal mill pulverizing system, coal mill output and lowest stable-combustion boiler load calculation and experiment was carried out. To ensure the absolute safety of the lowest stable burning load of the unit in depth peak shaving and the unit in the lowest stable burning condition in abnormal conditions such as coal cutting, avoid blind fuel injection and steady burning, reduce ineffective operation and save fuel.