Abstract: Handan Coal Washery currently has two 3-product H.M. cyclones, which can get plugged up in routine operation by foreign matters or large pieces of coal particles. The plugging of cyclone cannot be noticed in time by the operator and at the time when the operator noticed it through abnormal screen discharge, some clean coal can unavoidably get into refuse. In this case, the cyclone cleaned coal mixed with refuse has to be completely rewashed for avoiding economical loss and quality-related complaint from users as they set a high requirement on dirt content and ash of cleaned coking coal. To be able to timely detect the plugging of cyclone for avoiding the occurrence of any severe accident has become a focal point for technical solution by the washery. Application of the plugging warning system makes it possible to timely detect the early sign of blocking and take technical means to interfer with the plugging phenomenon, or immediately take corresponding measures to avoid the loss of clean coal in refuse upon detecting the plugging of cyclone.