Sectional coal pillar protection roadway is designed between 4209 and 4207 working faces in Huangling Jianxin Coal Mine. In order to determine the appropriate width of coal pillar, the distribution characteristics of plastic zone with different coal pillar widths are discussed by means of numerical simulation, similar simulation and field measurement, and the appropriate width of coal pillar is determined. The evolution characteristics of roadway and coal pillar displacement field under appropriate coal pillar width are studied by similar simulation, and the stress monitoring and analysis are carried out in combination with the field.The results show that when the coal pillar width is less than 9 m, the coal pillar is greatly affected by the mining disturbance, and the plastic zone of the coal pillar in the goaf is connected, and the risk of coal pillar instability is high. When the width exceeds 15 m, the elastic core area increases but the coal resources are wasted. Finally, the reasonable range of coal pillar width is 9 ~ 15 m. By simulating the deformation characteristics of coal pillar and roadway surrounding rock in different mining stages under 9 m coal pillar, and monitoring the borehole stress of 9 m coal pillar at the same time, it is found that with the advancement of mining process, the deformation of coal pillar and roadway surrounding rock gradually increases, but the overall deformation is very small, and the internal stress of coal pillar also shows an upward trend, but the stress increment and stress change rate are very small, and the closer to the coal pillar, the smaller the internal change is. It is determined that the 9 m width coal pillar meets the economic benefits. At the same time, although there is a certain damage area inside it, there is still a certain integrity and stability, which meets the requirements of mine safety production. The research results can provide theoretical basis and engineering reference for coal pillar design under similar geological and mining conditions.