Under the action of horizontal deformation of groundsurface in mining area,the difference of horizontal deformation between groundsurface and building foundation will produce mutual echanical interaction.To obtain the additional stress components of building foundation under the action of horizontal groundsurface deformation,this research takes the react force of building foundation as the normal force acting on the lower surface where the friction force is produced by it.The calculation formula for additional stress of building foundation are derived by means of center-offset stretching (compression) methods,where the side stress of square foundation are derived based on thetheory of Rankin soil packing theory.The research shows that: the longitudinal additional stress magnitude of building foundation under mining effects is related with the foundation factor,the friction factor between foundation and groundsurface,and the length of foundation.The maximum effect on additional stress is originated from the accumulation effects of foundation length.Under the action of groundsurface compressing,the side wall of foundation is compressed by the groundsurface soil,the additional stress magnitude is related with the square of foundation depth and soil features.When the depth of foundation is large,the effects of side pressure of foundation on the additional stress of foundation should be taken into consideration.