The transportation roadway of No. 8717 Face in No. 5 Mine of Yangquan Coal Industry was taken as the engineering background, the reasonable width of section coal pillars under strong dynamic pressure conditions was investigated by combining theoretical analysis and three-dimensional numerical simulation. Based on the distribution characteristics of lateral abutment pressure in the goaf and the limit equilibrium theory, a calculation model for the plastic zone width of coal pillars was established, and the reasonable width range of section coal pillars was theoretically determined to be 8.65～10.23 m. Numerical simulations were conducted for coal pillar widths ranging from 6 to 20 m to comparatively analyze the stress distribution, deformation characteristics, and plastic zone evolution of the coal pillars and surrounding rock of the roadway. The results indicated that increasing the coal pillar width could effectively reduce the influence of mining-induced stress on the roadway surrounding rock. When the coal pillar width was less than 10 m, the plastic zone was extensive and prone to penetration, which was unfavorable for roadway stability. When the coal pillar width reached 10 m or more, the plastic zone was significantly reduced and no longer penetrates, resulting in a marked improvement in the overall stability of the roadway. Based on comprehensive analysis, the reasonable width of the section coal pillar was determined to be 10 m.