Abstract: The KDZS-II type coal body gas instantaneous desorption and seepage characteristic tester was used to analyze the effective stress sensitivity of 3^# coal seam in Xinjing Mine under the gas pressure conditions of 0.31 MPa and 0.61 MPa. The results show that the permeability of 3# coal seam in Xinjing Mine is extremely sensitive to effective stress, and the permeability of coal seam decreases with the increase of effective stress, and there is a good negative exponential power function relationship between them. The permeability changes of different coal sample specimens under the same gas pressure and effective stress are different and the differentiation phenomenon is significant. The permeability of the coal sample specimens is closely related to the porosity and fracture direction. When the fracture direction of the coal sample specimens is parallel to the axial direction and the porosity is large, the permeability of the coal sample specimens is relatively large. When the fracture direction of the coal sample specimens is perpendicular to the axial direction and the porosity is small, the permeability of the coal sample specimens is relatively small.