The study of the law of mine pressure appearance is very important to ensure the safe and efficient production of coal mines. In this paper, No.182813 fully mechanized mining face of No.2 coal seam in Wutongzhuang Mine of Jizhong Energy was taken as the research object, and the law of mine pressure appearance in the mining process of the working face was analyzed based on FLAC 3D software system. By establishing a three-dimensional numerical model, the roof subsidence and stress distribution during the advancement of the working face were simulated. The research results showed that FLAC 3D could better predict the law of mine pressure in the working face. With the advancement of the working face, the roof subsidence area continued to expand, from the initial local settlement to the overall deep settlement, and reached a peak at about 60 m. It provided guarantee for safe and efficient production of No.182813 fully mechanized mining face, and provided theoretical basis and technical support for safe and efficient mining under similar geological conditions.