Low-rank coal usually has high moisture and high number of oxygen-containing functional groups, such as hydroxyl, carboxyl, and carbonyl, which will make the coal surface more hydrophilic. In general, low-rank coal is difficult to float using direct froth flotation, the method of floating coal particles by strengthening the hydrophobicity, even with a large dosage of oil collectors. In this research, reverse flotation was applied to upgrade subbituminous coal. The effect of different conditional factors on the reverse flotation performance of subbituminous coal was investigated, and a clean coal product with 8.41% ash content could be obtained under reasonable flotation conditions.