Abstract: In order to explore supercritical methane adsorption characteristics, we propose supercritical methane adsorption isotherm and take it as research basis. We plotted the adsorption characteristic curve that adsorbed phase volume changed with adsorption potential at different temperature by the adsorption potential theory. The results show that the adsorption characteristic curve under different temperature can be represented by a curve or unified equation, which theoretically verifies that the adsorption of supercritical methane on coal surface also depends on the dispersion force and has no relation with temperature. The methane adsorption model was established based on the adsorption characteristics. We realize the goal of predicting supercritical methane adsorption capacity under different pressure and temperature according to isotherm test data, which overcomes the limitations of existing isothermal prediction. But, when the temperature exceeds a certain scope, the density of adsorbed phase can not be replaced by limiting density; due to the molecular rearrangement, the change of adsorbed phase density, it results in the increasing prediction error.