By using substructure method, the superstructure can be condensed to the interface of the superstructure and the raft, and the governing equation of the superstructure is obtainable. The governing equations of the raft are obtained based on the thin plate theory and the virtual work principle. By employing the elementary solution of the vertical force applied on the surface of the layered viscoelastic saturated soil and the compatibility conditions between the raft and the layered soil, the governing equation of the interaction between soil and raft is established. Laplace transform is applied to the obtained governing equations and the governing equations in transformed domain are gotten. Solving the governing equations in transformed domain and applying the corresponding inverse transform, the proposed interaction problem can be solved.