The ZGM113G vertical coal mill has some problems such as high pressure difference in grinding, large vibration value, large slag discharge, low grinding efficiency, and the output cannot meet the requirements of cement production. Based on the analysis and analysis of the actual operating conditions of the coal mill and the internal and external factors affecting the production, some measures were taken, such as adding a hot air settling chamber, reforming the grinding area and reforming the powder separator. After the transformation, the system runs stably, the slag spitting amount is reduced, the equipment failure rate is reduced, the mill output is increased from 35t/d to 45t/h, the yield increase is 28.5%; The main motor current of the mill is reduced by 9A and stabilized at about 65A, and the power consumption of the main motor is reduced by 0.5kW?h/t.