Abstract: Coal gasification fine slag is a solid waste produced in the process of coal gasification. At present,it is mainly treated by landfill.However,due to its high carbon content,it still has certain utilization value. Carbon and ash separation is the key to realize its reduction and resource utilization. Taking coal gasification fine slag in Yulin as the research object,the decarbonization test was carried out by flotation method. Based on the analysis of basic characteristics,the influence of different flotation conditions and processes on separation effect was studied. When the amount of diesel oil is 14 kg/t and the amount of sec-octyl alcohol is 14 kg/t,the ash content of concentrate product is 37.88%,the ash content of tailings product is 51.65%,and the combustible recovery is 51.99% after roughing separation. The concentrate ash content of 18.87% and the yield of 20.30% can be obtained by one roughing one cleaning and one scavenging flotation process when the amount of diesel oil is 14 kg/t in roughing and the amount of diesel oil is 7 kg/t in scavenging. The final calculation shows that the concentrate yield is 41.76%,the ash content is 27.92%,and the combustible recovery is 55.08%. The carbon and ash in the coal gasification fine slag is well separated by one roughing one cleaning and one scavenging flotation process,but the flotation reagent consumption is too high,and the fine materials are more likely to float up into concentrate products in the roughing process. The addition of reagent in the scavenging process can make the coarse materials float up effectively,resulting in the phenomenon that the ash content of the scavenging concentrate is lower than that of the cleaning concentrate. The surface morphology analysis,pore structure analysis,surface functional groups analysis and float and sink analysis of coal gasification fine slag samples show that the samples with large specific surface area and developed pore structure are easy to absorb a large amount of reagents,resulting in excessive consumption of flotation reagents and poor economy.