Abstarct: The sudden explosion of methane during underground coal mining is a major dilemma. To mitigate its occurrence and reduce the extent of methane diffusion, gas drainage operations are carried out before mining. This thesis investigates methane gas flow in a coal block in order to calculate the pressure of gas and its molecule velocity for methane gas drainage operation. The geometric model used in this study has similar assumptions about coal.For this purpose, samples of coal were selected from the studied mine, which is the Parvadeh Tabas coal mine in Iran. After coring, the permeability, porosity, and specific gravity were measured. Using microscopic imaging, it was also used to identify the masses in order to determine the effect of maceral on permeability. Using the CT scan, the distance between the coal cleats was determined. The parameters necessary for modeling were obtained through experimental analysis. A coal block surrounded by cleats was used for geometrical modeling and numerical simulation. Movements of fluid and gas molecules in a porous medium were successfully simulated. The numerical solution is baxsed on COMSOL Multiphysics software. The velocity of methane gas molecules was obtained 0.0269 m / s in Tabas coal samples. In previous studies, this value is calculated to be 0.005 m / s, and the results are acceptable in terms of validation.