Reducing the width of coal pillar is one of the ways to improve the coal recovery rate, before adjusting the width of coal pillar, the FLAC3D numerical simulation software was used to analyze the stress of coal pillar in Zhaozhuang Mining Industry, the lateral stress of working face and the displacement field of roadway under the width of 8 m, 30 m and 55 m，Through analysis, it can be concluded that the stress concentration degree of coal pillar was high, the deformation of roadway was severe, which was not conducive to the maintenance of roadway section, before adjusting the width of coal pillar, it is necessary to carry out industrial tests, such as pressure relief of coal pillar and strengthening support.