Abstract: In order to increase the quality and yield of flotation clean coal,lower the production cost,developed the flotation automatic dosing device based on the radiation density meter,electromagnetic flow meter,and PLC variable-frequency controller,metering pump and MCGS touch screen,and it has been put into use in Hengfu No. 1 coal preparation plant. The operation results show that this device can increase the quality and yield of clean coal,reduced reagent consumption and also reduced the labor intensity of workers.