During coal extraction, a protective pillar is left between two facing walls to support and safeguard the roadway. The width of this pillar plays a crucial role in determining its load-bearing capacity. A wider pillar can waste coal resources by exceeding capacity, while a narrower one may not provide sufficient support for the roadway. This study focuses on how pillar width affects load-bearing capacity, using data from a mine in Shandong province. The study employs theoretical analysis and numerical simulation software to analyze the plastic zone and vertical stress distribution within the pillar, as well as how these factors change with varying pillar width. The findings indicate that wider pillars have a larger elastic core area and lower peak stress levels.