Abstract: This is is an article in the field of mineral processing engineering. In this study, the controllable factors such as the amount of collector used in the flotation, the amount of foaming agent, the ore feeding rate and the aeration amount were changed,we conducted a column flotation comparative test study on fine coal with or without nanobubbles. On this basis, the recovery mechanism of nano-bubble to fine coal was expounded. The test results show that nano-bubbles can improve the recovery rate of ultra-fine coal particles, save about 1/2 of the dosage of the agent under the same ash content, and play the role of the second collector. In addition, the use of nanobubble flotation can still obtain a better sorting index under the condition of lower airflow velocity. Nanobubbles can be preferentially adsorbed on the surface of hydrophobic particles to make fine-grained coal agglomerate into larger particles, enhancing the collision probability of conventional bubbles and coal particles to achieve the effect of enhanced flotation.