Abstract: The main key layer has a significant impact on the movement of the overlying rock and the advanced abutment pressure of the working face.This article uses UDEC7.0 software to establish a numerical model, setting three schemes with distances of 20 m, 100 m and 200 m between the main key layer and the old roof, and analyzing the overburden movement and advanced abutment pressure laws under different schemes.The results show that the higher the main key layer, the longer the time required to participate in the movement of the overlying strata, and the longer the stability time of the overlying strata; An increase in the thickness of soft rock will limit the development of fracture zones and increase the height of curved subsidence zones; The distance between the main key layer and the old roof increases, and the maximum subsidence first decreases and then slows down.The required step distance for stable subsidence is linearly related to this distance; The influence of the main key layer on the peak value of the advanced stress is not significant in the early stage of mining.Afterwards, the peak values of each model have different trends, and after settling, they tend to stabilize and the difference decreases; The farther the main key layer is from the old roof, the larger the range of influence of the advanced abutment pressure under the same advancing step, and the larger the final stable value.