Abstract: In order to overcome the difficulty of traditional foundation deformation calculation using a single constitutive model of geotechnical materials, the calculation method is single point by point only in the category of elasticity, the distributed grid sub-domain system was developed, the theoretical formula of calculating effective additional stress in the soils was derived, the method for calculating vertical deformation of layered soils subjected to additional load was established. The SSBS analysis program for vertical deformation of layered soil is compiled based on MATLAB language platform, Drucker-Prager elasto-plastic constitutive model is adopted in combination with the measured data of the project, then the vertical deformation of the base of the layered soil under the large foundation is calculated and analyzed, calculation results are verified by the theoretical and engineering measured data, the proposed calculation method and analysis program can effectively solve the problem of layered soil foundation deformation.