Abstract: The deformation of bridge-approach foundation is the key factor to cause that of bridge abutment, so the study on the bridge-approach deformation contributes to the further study on abutment deformation. Based on the elastic theory, a formula for additional stress of bridge-approach foundation and adjacent surroundings under an arbitrary subgrade section load is derived. The distribution rules of additional stress of approach foundation under a standard railway embankment section load are obtained, and the response of the adjacent buildings to the approach foundation under the subgrade load is analyzed. On this basis, the rationality of the formula is verified by means of numerical simulation. The results show that the proposed method is clear in thought, mathematically logic, and easy in programming. It may provide the theoretical basis for calculation of additional stress and the theoretical support for the studies on abutment deformation.