By means of floatation, an experimental study was made on the separation of unburned carbon from fly ashes in an area of Hunan, whose carbon mass fraction was 23.12%. The optimum roughing conditions were obtained through orthogonal tests that floatation time was 5 min, the dosage of collector (light diesel oil) was 1100 g/t, and the dosage of frother (FR) was 800 g/t. The experiment process was one roughing separation and two concentrating separation. The experiment results showed that after floatation the carbon mass fraction in concentrates was 63.5%, the recovery was 88.02%, and the tailings could reach the 1st and 2nd grade of national fly ash standard, which could create better social and economic benefits.