Abstract: By establishing the equilibrium equation of swelling rock boreholes in coal mines, considering the expansion and softening properties, the elastic-plastic mechanics analysis was carried out, and the plastic zone radius and radial displacement of the surrounding rock of the swelling rock in coal mines were determined under the coupling of humidity and stress field. According to an example based on the research background of the floor rock roadway in the 8^# coal seam of Songzao Coal Mine in Chongqing, the calculation results were carried out, and the influence of water content, ground stress and water pressure inside the hole on boreholes shrinkage was studied. The results show that with the increase of the ground stress p, the radius of the plastic zone and radial displacement of boreholes walls are increasing, showing a significant nonlinear relationship. The presence of water exacerbates the influence of ground stress on boreholes shrinkage in coal mines. The larger the water pressure in the boreholes, the smaller the radius of plastic zone and radial displacement of boreholes walls, and properly increasing the water pressure in the boreholes can effectively control the boreholes shrinkage.