Abstract: With the gradual increase of coal mining intensity, a large number of safety coal pillars are left in the stope. The stability of these coal pillars and their overlying strata determines the safety of the whole stope, overlying rock and even the surface. Once the overall failure and instability of the composite system occurs, it will lead to many disastrous consequences. In this paper, the theoretical model research and mechanical behavior of roof pillar combination at home and abroad are summarized and reviewed, and some new opinions on the stability of the combination are proposed.