Abstract: Aiming at the leakage of powder resin in the fine-processing powder filter of an air-cooled power plant, the concentration of suspended particles in condensated water and the effluent of powder filter of a 2×600 MW supercritical aircooled coal-fired unit is monitored and analyzed. The results show that the suspended particles in condensed water are mainly distributed from 2 μm to 10 μm. When there are a large number of particles over 10 μm in the outlet of the powder filter for a long time, it is determined that the filter is leaking. The end point of membrane spreading should be 180 min, which can effectively reduce the leakage of powder resin. However, when the filter is put into operation, the influent flow fluctuates, and the total particle number increases obviously. In the middle period of operation, the filter efficiency of the powder filter is stable, and at the end of operation, the filter efficiency and the quality of the effluent water are decreased obviously, so the current index of filter separation should be adjusted.