Abstract: In order to explore the key points of controlling the stability of surrounding rock with coal pillar width, ensure the coal mining rate, and improve the strength and bearing capacity of coal pillars. Based on the current theory and technology of coal pillar width design, taking the design of coal pillar width in the surrounding rock of Dongjiang mine as an example, relevant supporting data is obtained by using peepholes, and then rock analysis is carried out in the laboratory to obtain the mechanical characteristics of the mineral. Finally, FLAC3D numerical simulation software is used for final width testing. The results show that if the preset width of the coal pillar is 6 m, it has good efficiency performance - maintaining the vertical and horizontal values, the maximum horizontal stress of the bottom plate, and other factors within the standard range, and has high coal mining efficiency.