Based on the theory of coordinating action of building ground, foundation and structure, this paper presents a modified method for calculating additional stresses on buildings in mining areas by considering the joint effect of curvature deformation and horizontal deformation on buildings. It points out that for buildings over the coal pillar, it is advisable to soften the intermediate ground of buildings when they are affected by mining. For buildings over the goaf, it is preferable to soften the ground at both ends of buildings. In order to enhance the ability of a building to resist tensile deformation, the key measure is to reinforce the bottom foundation of the building. In addition, the concept of "angle of break of building" is proposed. It is because of this angle that the protecting coal pillar is left, which is a better solution than prevailing solutions The findings provide a more scientific basis for mining under buildings.