Abstract: Aiming at the unstable roof of8₂20 machine roadway in 7₂20 face of Jiegou Coal Mine, the width of plastic zone on one side of coal pillar and the stress distribution law of upper coal seam floor are studied by using limit equilibrium theory and elasticity mechanics theory. The results show that the width of plastic zone on one side of 7^# coal pillar is 21.1 m. After mining of the upper coal seam, the stress balance state of the original rock is broken, and the stress concentration area and pressure relief area appear near the coal wall. The maximum damage depth h_max of floor is 15.91 m, the maximum damage depth of floor is 7.41 m from the horizontal distance of coal wall and 84.3 m from the horizontal direction of floor damage area of goaf. According to the relative position of the left coal wall of the goaf in 7^# coal seam and the central line of the roof of the mining roadway in 8^# coal seam, four sets of layout schemes are proposed. Through comprehensive analysis, when the distance between the coal wall and the central line of the roof of the mining roadway is 22 m, the stress of the mining roadway is small and even, the distribution of the plastic zone is small, and the deformation of the surrounding rock is also small.