Abstract: The thinning and rupture of the hydration film at the solid-liquid interface are the key factors affecting the flotation performance. In order to clarify the influence of mineral surface wettability changes on the hydration film,graphite was used as the research object,and hydrogen peroxide and surfactants were used to regulate the surface wettability of graphite. The structure and thickness of the hydration film were directly characterized by Atomic Force Microscopy (AFM),and the mechanism was studied. The results showed that the thickness of the hydration film increased with the degree of graphite oxidation, and the hydrophilic polar groups increased by oxidation mainly increased the thickness of the ordered layer in the hydration film;The surfactant adsorption can effectively cover the oxygen-containing groups on the mineral surface,thereby changing the structure of the hydration film. The ordered layer in the hydration film transformed to the transition layer,which can reduce the thickness of the ordered layer under low surfactant concentration,while the excessive adsorption of the surfactant could only increase the thickness of the transition layer,and the thickness of the ordered layer would not change significantly. In the flotation process,a small amount of excess agent is beneficial to the thinning and rupture of the hydration film on the hydrophilic mineral surface.