The sliding instability law of overlying rock layers in fully mechanized top-coal caving longwall face is an important theoretical topic in the study of mining pressure manifestation. In order to study the stability problem of the end roof of the fully mechanized caving face, based on the fracture mechanics theory of the end roof, a hinge mechanics model between the fractured rock blocks of the end roof of the fully mechanized caving face was established. The stability of the end roof was studied, and the deformation and instability law of the end roof plate body structure was obtained. The research results indicate that the rotation subsidence of the curved triangular block roof along the end of the working face is inconsistent. As the support resistance force increases, the rotational subsidence of the roof gradually decreases. The study on the stability characteristics of the overlying rock structure in the fully mechanized mining method provides a theoretical reference for achieving safe control of mining pressure in the mining area.