Abstract: The yield and total ash content of middlings coarse coal slime,+ 0. 18 mm,are 61. 86% and 26. 15% respectively according to screening & float-and-sink test of these slime in Suncun coal preparation plant,which show that plenty of clean coal included in these slime need to be collected. Not only is separation technology improved,but the problems of actual production are solved by using three taper angles hydrocyclone,new equipment separating coarse coal slime,to separate middlings coarse coal slime as well as combining with heavy medium & flotation technology. The clean coal yield are improved by 0. 51% at the same time sales revenues are increased by 3. 465 million each year after modification.