Based on the theory of interaction between deep excavation support structure and subsoil, the influencing coefficient is presented in this paper in the condition of different foundation model. The calculation result shows that the foundation deformation considering interaction among soil springs is large than those not considering the interaction, and also larger than engineering practical condition. Theoretical analysis indicates the stiffness change of soil spring is related to spring rigidity in both active region and passive region when it is calculated by incremental method. The example proves that the method presented in this paper has good preciseness comparing with the results of engineering practical condition. So the theory of incremental method of deep excavation considering interaction is consummated.