The thick layer spoil dump changes the self-weight stress field of the lower working face mining, which directly affects the safe mining of the fully mechanized caving face. By using the methods of theoretical analysis, numerical simulation and engineering measurement, the mine pressure and strata movement characteristics of the first mining in No.13103 fully mechanized caving face under the dump of Shaping Mine were studied. The results showed that there were many key strata in the overlying strata, and the key strata near the stope determined the roof breaking step. The dump changed the vertical stress distribution characteristics of the working face, and the vertical stress difference under the influence of the original landform and the dump was more than 2 MPa. The characteristics of ground fissures verified the initial O-X fracture mode. Through observation, it was found that the floor heave occurred in the middle of the primary subsidence basin under the old dump. The internal cracks and front and back pulling cracks of the working face were parallel to the working face, and the lateral pulling cracks intersected with the working face at different angles. The research work provided a reference case for the prevention and control of geological disasters and the study of mine pressure in the working face under the dump.