Abstract: In order to rationally set up the width of the sectional coal pillars in the coal mining face of Duizhen Mine, on the premise to ensure the support stability 0 f the gateway, the width of the coal pillar left should be reduced and the coal mining rate should be increased.With the measurement and test on the physical mechanics parameters of the coal and rock mass with the coal and rock samples collected from the seam as well as the roof and floor, the FLAC3D numerical analysis software wa s applied to establish the mechanics model of the different width sectional coal pillars in the mining process.The comparison and analysis was conducted on the differen ces of the surrounding rock stress, deformation and plastic zone distribution law when three different widths of the coal pillars applied.The results showed that the coal pillar with a width of 16 m could be well to reduce the stress concentration degree of the coal mass during the advancing process of the coal mining face, the plastic Z0 ne scope and the lateral deformation value and could reduce the coal pillar width. Finally the rational section coal pillar width was determined as 16 m and the coal mini ng face could realize the safety mining.