Based on the engineering background of gob-side entry driving in No.1308 Face of Yineng Mine, the Trigon model was established based on the field geological conditions by using UDEC numerical simulation method, and the model was corrected. The roadway deformation, coal pillar cracks and stress distribution characteristics were studied when the coal pillar width was 4,6,8 and 12 m. The numerical simulation results showed that under the width of 6 m coal pillar, the deformation of roadway surrounding rock and the distribution of internal cracks were relatively reasonable, and the stress distribution was more balanced in key parts. After carrying out industrial experiments, the monitoring results showed that the overall control effect of the roadway was good. The research results could provide a useful reference for the stability of roadways under different coal pillar widths in gob-side entry driving.