Abstract: In order to study the stability of the “filling body-coal pillar” composite bearing structure, the 4901 working face of Shaqu Coal Mine is taken as the engineering background, the stress changes and failure characteristics of the composite bearing body were explored through laboratory tests. The composite bearing body was divided into four categories by means of numerical simulation. The stability of the supporting body under different types, widths, heights and different strengths of the filling bodies and coal pillars is analyzed. The results show that: with the increase of support width, the width of the elastic zone increases significantly. The average width of the elastic zone increases by about 6.02% when the width of the support is 30 m than the width of 20 m, and the average increase of the width of the elastic zone by about 34.35% when the width is 40 m and the width of 30 m. Compared with the other three types of the four types of composite supports, the width of the plastic zone of the type IV support is relatively small, and it keeps fluctuating within a small range as the retention charge ratio increases, and the stability effect is the best. As the height of the support increases, the stability decreases, but the strength of the filling body and coal pillars increases, and the stability of the support increases.