Abstract: In a 1000 MW ultra-supercritical reverse double tangential circular combustion boiler produced by a boiler factory, due to the large deviation of primary air powder, the water wall tube No. 313 in front of the furnace was seriously overheated during the load lifting process. By repeatedly adjusting the adjustable shrinkage hole of the powder delivery pipeline and adding online measurement, the primary air powder is adjusted to level the average speed of the primary air powder before adjustment exceeds the design value by 3%, the maximum primary wind speed deviation reaches 19.1%, and the concentration deviation of pulverized coal at each corner reaches 46.3%. After adjustment, the primary wind speed and powder quantity deviation are reduced to 6.9% and 25.1% respectively, and the wind speed is reduced by 3% on average. Under the condition that the boiler load rate and operation mode are basically the same after the air powder leveling and the air powder velocity lowering, the overtemperature statistic time and the overtemperature statistic times of the water wall tube No. 313 in front of the furnace are reduced by nearly 78% and 74% respectively. The maximum amplitude of the overlimit was reduced from 571.7 ℃ to 486.3 ℃, reducing by nearly 85.4 ℃, and the overtemperature phenomenon of the water cooling wall was sharply reduced, effectively improving the safety and flexibility of the unit. The results can provide guidance for the operation adjustment of boilers of the same type.