Abstract: This is an essay in the field of mineral processing engineering. In this essay, the particle size characteristics and mineral composition of the Kaida coal sample in Ordos City, Inner Mongolia were studied. Meanwhile, based on the results of the previous single factor test, the orthogonal test was used to investigate the impeller speed, aeration amount, the dosage of the collecting agent and foaming agent on the flotation perfection index and the recovery rate of combustible material. Finally, the "one roughing and one cleaning" flotation process was used to further study the optimal scheme of the orthogonal experiment. The results show that the primary and secondary order of the factors is the dosage of foaming agent > the dosage of collector > the impeller speed > the aeration dosage. The optimal scheme obtained from the orthogonal experiment is A₂B₂C₃D₃, that is, the dosage of frother is 800 g/t, the dosage of collector is 1600 g/t, the slurry concentration is 60 g/L, the impeller speed is 1800 r/min, and the aeration dosage is 0.175 m³/(m²/min). Under the optimal conditions, after the "one roughing and one cleaning" flotation process, a clean coal with yield of 49.41%, ash of 8.70%, and a tailing coal with yield of 50.59%, ash of 74.15% were obtained.