Abstract: Taking the geological condition of a mine in east as the background, this article studies gob-side entry driving coal pillar leaving in the special thick coal seam of this mine by using FLAC^3D finite element software, and analyzes three-dimensional stress field of surrounding rock in thick coal seam sub-level caving mining stope. The results show that vertical stress is 23.98 MPa, stress concentration area in coal within 13 m to 30 m. when the width of the coal pillar is about 20 m to 24 m, the stress peak value under the pillar is not large, the displacements of the roof, the floor and two siders are small. Therefore, the pillar is relatively stable, the maintenance of the gateway becomes easy and the recovering rate is enhanced.