Abstract：Based on the self-developed triaxial seepage testing system of coal containing gas, a large number of permeability experiments for loaded coal containing gas under different testing conditions are implemented, then similarities and differences of permeability between the permeability of CO 2, CH 4 and N 2 are analyzed comparatively in detail. The results show that the permeability of coal samples decreases with the increase of confining pressure, and the decreasing rule obeys a negative exponential law under the condition of a fixed gas pressure condition. Under the condition of fixed confining pressure, the permeability of coal samples decreases with the increase of confining pressure and shows a power function law. The permeability for different absorption gas shows that the stronger the gas absorbing capability is, the lower the gas permeability is. In an axial loading case, the permeability of different gas shows a trend of first decrease and then increase and displays nearly a shape of letter“V”. The research results have a certain theoretical value for deeply understanding the migration law of coal seam gas.

Keyword：adsorbed gas;loaded coal containing gas;seepage property;permeability;