Abstract: In order to study the seepage characteristics of low permeability coal samples in the process of whole stress-strain, in this paper, the experimental results come from the whole stress-strain process seepage test of low permeability coal sample, which are taken from Zhangji Coal Mine. Furthermore, combining with Darcy's law and the theory of solid mechanics, the numerical simulation of internal gas permeation properties of specimen is conducted based on the experimental results by using COMSOL Multiphysics. The numerical simulation results show that the methane gas in the process of unsaturated seepage in the coal sample, gas pressure distribution of nonlinear phenomenon is obvious. But as the infiltration time ahead, the gas pressure distribution law gradually tends to be linear. Confining pressure and the yield strength is positively related to relationship, and negatively correlated with permeability. What's more, fluid-solid coupling seepage effect of low permeability coal is more obvious.