Abstract: Product upgrading and improvement of economic performance at Shigetai Coal Preparation Plant are subject to the restriction imposed by a series of factors. Based on the result of an in-depth analysis of the causes giving rise to these factors,a technical innovation and economic improvement scheme is proposed and put into practice. The successful implementation of the scheme makes it possible for the plant to realize effective recovery of middlings with shallow-trough heavy-medium separator,pre-removal of degraded fine slime from coal washing system,automatic control of 10 air compressors by groups and grades,increase of yield and calorific value of saleable coal and efficiency of slurry treatment system,cutdown of operating cost,reduction of load imposed on slurry treatment system,and increase of production efficiency.