Abstract: The difficulties confronting Longquan Plant are high loss of coal in refuse and increasing drop of yield of clean coal due to deterioration of raw coal property and low separation sharpness. To tackle the problems, work is made on technical reform of the existing coal washing process with the use of S-3GHMC550/440/320 super H. M. cyclones. Practice shows the use of these cyclones can effectively separate the raw coal of Longquan Mine thanks to their high capacity, separating precision and adaptability, and lead to proper increase of ash of clean coal, reduction of losses of middlings, increase of calorific value of middlings, reduction of energy consumption and improvement of economic performance of the plant. The renovation work made may serve as a reference for the reform and upgrading of other coal preparation plants.