Abstract: Because of the deterioration of the quality of the plant′s raw coal feed year by year, work is made on the technical transformation of the raw coal screening system based on the property of the < 8 mm raw coal and the effect as well as the economic efficiency obtained through the renovation are analyzed. Practice shows that through lowering the classification size of raw coal from 13 mm down to 8 mm and adjustment of related process links, there have been seen a prolonged service life of screen plates, increased aggregative yield of products, reduced yield of coal slime and consumption of flocculants. This not only ensures that the out-loaded coal is up to the required standard, but also brings forth further improved economic benefit for the plant.