Abstract: With an aim to reduce the ash of the cleaned coarse-grained slime for attaining a higher yield of clean coal product, work is made by Luxi Coal Preparation Plant on the technical transformation of the cleaned coarse slime treatment process, with the application of the DZSN3028 3-mass intelligent high-frequency fine screen to replace the sieve bend originally used. Practice shows that with the use of the fine screen, the problems previously encounted, such as water leakage, presence of oversize in undersize material and high ash of oversize material, have been eliminated, making it possible for the screen oversize to reduce its ash from 11.21% to 9.00% and its content of > 0.3 mm size to rise from 80.10% up to a high level of 91.71%.