Abstract: The finite volume method is used to carry out numerical simulation for the gas emission laws of excavation roadway coal wall in thin and medium thick coal seam. It is studied that the influence of dynamic change of coal permeability on coal wall gas pressure distribution and gas emission rate in the process of stress redistribution of excavation roadway coal wall. The results show that the coal permeability in roadway coal wall determines the coal gas pressure distribution and gas emission rates, the dynamic change process of coal permeability should be considered to investigate gas emission rates in the whole process after the exposure of excavation roadway coal wall.