In the case of working face mining, the reasonable setting of the end pillar width is the key factor to maintain the stability of the roadway.Reasonable setting of the pillar can not only effectively improve the recovery rate of coal resources, but also maintain the stability of the roadway.In this paper, 6102 working face of Chuancaogedan Coal Mine is taken as the research object, and the reserved size of the end coal pillar is studied by means of numerical simulation and theoretical analysis.Through the limit equilibrium calculation of the coal pillar, the reasonable upper and lower limits of the coal pillar size are determined to be between 15.00 m and 32.54 m.Combined with numerical simulation, and according to the stress and plastic zone distribution of roadway surrounding rock in five schemes, including 30.0 m, 25.0 m, 22.5 m, 20.0 m and 15.0 m, the width of the end coal pillar is determined to be 23 m.At this time, the advance support stress of the working face has little impact on the connecting roadway, and there is an elastic core area of about 10 m in the coal pillar, which can ensure the stability of the coal pillar and prevent the gas in the goaf from flowing into the connecting roadway.The research results have been successfully applied to engineering practice, which provides a useful reference for the retention of coal pillars under similar conditions.