At present, the calculation of foundation settlement is mainly based on the parameters of soil layer obtained from laboratory tests, and the settlement is calculated by layerwise summation method. However, the parameters of laboratory tests are often affected by sampling disturbance, which is quite different from the original soil, especially the hard soil with unique structure. The settlement calculated from the compressive modulus of laboratory tests is quite different from the actual settlement. In this paper, the tangent modulus equation between tangent modulus and stress level of undisturbed soil is established through plate loading test of undisturbed soil foundation to calculate settlement of layered soil instead of the compression modulus. The tangent modulus method can also be used for settlement calculation of layered soil. As long as the parameters of the tangent modulus method for each layered soil foundation are obtained, that is to say, these parameters can be used to calculate the tangent modulus of each soil layer at different depths instead of the compression modulus of the general layerwise summation method, and then the settlement of multi-layer soil foundation can be calculated. By comparing the settlement of homogeneous soil foundation and layered soil foundation, it is verified that the tangent modulus method can reflect the influence of different soil parameters on settlement.