In response to the problem of large thickness of the 3# coal seam in Gaohe Mine and a large amount of coal resources waste by setting up section protection coal pillars, it was proposed to adopt the technology of gob-side entry retaining to improve the coal resource recovery rate. By using theoretical analysis, engineering analogy, and numerical simulation methods, a reasonable width of 1.5m for the filling body next to the roadway was determined. The on-site test was conducted in No.E1302 track roadway, and the monitoring data of the deformation of the surrounding rock in the roadway showed that when the width of the filling body was 1.5m, the deformation of the surrounding rock in the roadway was not significant, and there was no obvious deformation in the filling body, which could meet the safety production needs of the next working face.