Abstract: To establish a quantitative relationship between adsorption characteristics and surface energy of coal, the pendant drop method is used to test the surface tension of different concentrations of APG (alkyl glucoside) solution at a constant temperature of 27 ℃. The sessile drop method is used to test the equilibrium contact angle of APG dropping on the surface of different kinds of coal samples. The results show that the equilibrium contact angles of APG on coal surface are much smaller than those of water on the coal surface. With coal metamorphic grade increasing, the contact angles of APG on coal surface increase first and then decrease, which is controlled by the coupled effect of intermolecular force between the APG and coal molecules, and the decreasing of hydrophilic functional groups. With coal metamorphic grades increasing, the surface energy and adsorption constants of coal samples decrease first and then increase. Surface energy increases with the adsorption constants a and the change law between the two parameters obeys exponential function better. According to the regression model, the surface energy of coal can finally approach 35.63 mN/m.