Abstract: To solve the problems such as low in medium recovery rate,imperfection of separation automatic control,high concentration of under flow of thickener and less ability of agent adding system existed in Yangchangwan branch of Ningdong coal preparation plant,analyzed the medium recovery system and coal slurry system,and taken corresponding measures,which effectively solved the problems above mentioned.The technology renovation effectively solved the problems in that branch,and lower the production cost,obtained certain economic and social benefits.