Abstract: According to the deep mining geological conditions of the No.6 coal seam in Cuijiazhai Coal Mine, the stress sensors are arranged along the width direction of the sectional coal pillar. The stress field characteristics of the coal pillar are measured during mining advancing. Based on the FLAC^3D numerical simulation software, stress field characteristics of coal pillar and overall stability of roadway surrounding rock are investigated at different widths of coal pillar. In comparison with the results of numerical simulation and in-site measures, the reasonable width of the coal pillar reduces to 5~7 m from the experience value of 20~23 m. Field practice shows that the method of decreasing coal pillar width can control the stability of coal pillar and roadway surrounding rock effectively and improve resource recovery.