Abstract: In order to study the feasibility of safe mining under the buildings and the large depth of mining under pressure, relying on the geological mining conditions of Gaojiapu Coal Mine, the strip mining parameters were theoretically calculated. We apply the bearing capacity of rock stratum and breaking distance of rock stratum to determine the relative position relationship between key layer and aquifer, establish a mathematical model, and propose the criterion for determining the stability of key layer affected by mining width. Further theoretical analysis of the key layer and coal pillar stability after mining face mining is carried out, and the strip parameters are calculated by FLAC^3D simulation. The results show that under the buildings and confined water with deep mining, the theoretical calculation shows that the mining width does not affect the stability of the main key layer; the stability of the retained coal pillar is good, the simulated crack mining ratio is 18, and the surface is finally flat. The sinking basin meets the requirements for safe mining under buildings and confined water, and is crucial to solve the initial tightness of mines and ensure safe production.