Abstract: In order to decrease medium consumption of slack coal processing system in Changping coal preparation plant,taking each link which consumed medium as research object,the causes of large medium consumption were analyzed from technology level and management level. The results showed that,imperfect medium recovery system of powder coal,poor effects of spraying screen and magnetic separator,nonstandard daily management of magnetite powder led to high medium consumption. The above problems were reformed by installing buffer board in chute of spraying screen,setting up coal retaining plate at the inlet of spraying screen,adding spraying process in the middle of spraying screen,installing 10 pieces of 2 mm screen mesh in overflow launder,preremoving medium,building concentrated medium storage tank near the mixed medium bucket in the main plant,shortening medium addition pipe,regulating magnetite powder quality and use management. After transformation,the medium consumption reduced from 2. 0 kg / t to 1. 5 kg / t,lower the production cost and increased the economic benefits.