Abstract: A power plant equipped with foster wheeler D-11 D type double inlet and outlet pulverizing system has the problem of insufficient output. In this paper,based on the theoretical calculation of the pulverizer output and the test adjustment of the pulverizing system,the reason of the lack of the pulverizing output was analyzed,and the output of the pulverizing system was improved. The results of calculation and test show that the output of pulverizer is positively correlated with the ventilation rate,and only adjusting the operation mode of pulverizer to increase the ventilation rate of pulverizer can not really improve the grinding capacity of pulverizer. With the increase of the opening of the damper and the increase of the air flow of the pulverizer,the amount of grinding coal increases and the pulverized coal becomes coarser. If the pulverizer ventilation is insufficient,only increasing the steel ball loading capacity to improve the grinding capacity can not effectively improve the pulverizer output. After the change of coal quality,in order to improve the power of the pulverizer,in addition to increasing the load of steel balls and improving the grinding capacity of the pulverizer,it is necessary to increase the ventilation capacity of the pulverizer and enhance the capacity of carrying pulverized coal. The main reasons for the insufficient output of the pulverizer are that the operation mode of the pulverizing system is not adjusted correspondingly with the change of coal quality and the grinding capacity decreases due to the insufficient loading of steel balls of the pulverizer. According to the test results,by increasing the loading capacity of steel mill and increasing the pulverizer ventilation rate adjustment measures,the air pressure of the main pipe of the hot primary air remains unchanged at 7.0 k Pa,and A,B,C three coal mill run capacity when the damper opening at 75%,the total air flow in the pulverizing system reaches 209 t/h,the total output of the pulverizing system increases from 128 t/h to 137.89 t/h,and the loading capacity increases from 280 MW to 320 MW. When the damper opening is set at 90%,the total output of the pulverizing system increases to 144.84 t/h,and the load capacity increases to337 MW. The total output and load capacity of the pulverizing system were significantly increased.