Abstract: A grand canonical Monte Carlo(GCMC) method is carried out to investigate adsorption of supercritical methane in layered pillared nanomaterial. In the simulation, layered pillared nanomaterial is modeled by the approach of Yi et al[6,7]with a uniform distribution of pillars. Steele′s 1043 potential is used for representing the interaction between a LennardJones(LJ) methane molecule and a layered wall in the GCMC simulation. The sitesite interaction is also used for calculating the interaction between methane of LJ fluid and pillars. The classical excess adsorption isotherms of methane with three different pore widths, are obtained at two supercritical temperatures T=207.3 and 237.0 K. The optimum adsorption pressures,corresponding to the greatest excess adsorption, are 2.4, 3.1 and 3.7 MPa in the pore widths 1.02, 1.70 and 2.38 nm at temperature 207.3 K, respectively. It can be found that the optimum adsorption pressures increase with the increase of temperature under otherwise identical conditions,which are 2.9, 3.6 and 4.9 MPa, respectively,corresponding to pore widths of 1.02, 1.70 and 2.38 nm at T=237.0 K. Simulation indicates that the GCMC method is a useful tool for providing the optimum adsorption pressure of supercritical methane in layered pillared nanomaterials.