Abstract: Improving coal methane production  is an important subject in the current research for coal methane exploration.Some researches show that, coal methane exist mainly as adsorption state in coal seam pores.Improving coal seam temperature can make gas change into free forms from adsorption forms,and improve its seepage-diffusion ability. According to the thermoelasticity, nonlinear Darcy seepage theory and porous medium thermodynamics principle, this paper studied the mechanism of improving coal methane production by heat injection. The multiphysical coupling equations were been established, including coal deformation equation,gas percolation equation and heat transfer equation. By means of COMSOL numerical software ,the numerical solution of coupling model was been proceeded .The results demonstrated that rising injecting heat could promote desorption of coal methane, improve the permeability, achieve the purpose of improving coal methane production. The research results could provide corresponding theoretical basis for engineering practices of exploiting coal methane by heat injection.

Key words: thermal-hydrological-mechanical coupling, dual porosity medium, coal methane exploition, permeability