Abstract: In order to explore the sensitivity of axial pressure, confining pressure and gas pressure on permeability of coal under non-isostatic deviating stress, seepage tests of different axial pressures, confining pressures and gas pressures under non-isostatic deviating stress were carried out by using the seepage test system of damaged coal-rock mass. The test results show that: the permeability of coal sample is the most sensitive to confining pressure, followed by gas pressure, then axial pressure is minimal; the permeability of coal sample is much more sensitive to confining pressure than axial pressure, the sensitivity of permeability to confining pressure is about 8.5 times that of axial pressure. Therefore, in the mining practice of the protective layer, the pressure-relief effect by reducing the vertical stress of the protected layer is better than that by reducing the horizontal stress.