In order to solve the problems of low separation efficiency and insufficient clean coal yield caused by high ash content ( 28.5 % ~ 32.1 % ) and high fine mud content ( -0.045 mm fraction accounted for 41.3 % ) of coal slime in Gucheng Coal Mine, this paper takes the new flotation reagent as the research object, and systematically explores the influence of reagent dosage, slurry pH value and stirring intensity on flotation index through single factor test, and compares it with the original kerosene-sec-octanol reagent system on site. The results show that under the optimal conditions of reagent dosage 1 200 g/t, slurry pH = 8.5 and stirring intensity 1 800 r/min, the yield of clean coal increases by 1.5 % and the ash content decreases by 0.5 %. The comprehensive separation effect is better than that of the original system. The new agent has significant advantages in enhancing the surface hydrophobicity of fine-grained coal and reducing the consumption of agents, which can provide technical support for the efficient separation of coal slime in this coal mine.