Abstract: Under earthquake excitation, the deformation of underground structures is restricted by the surrounding soil media. The dynamic behavior of it displays quite differently from aboveground structures. Considerable progress has been made on the design and research of the underground structures since seventies-eighties of twentieth century. However, in the main, the widely used computational methods and guidelines in engineering design practice are based on rather simple assumptions, in reality, the actual soil conditions might be much more complex than ideally boundary conditions. Recent achievements of earthquake research on underground structures lie in the development of various computational methods for wave scattering problems of underground structures, such as the wave function expansion method, the boundary integral equation method etc. As the computation is somewhat complex, which impedes its application and dissemination in the engineering design practice. The author devotes himself to the improvement of the computational model for seismic analysis of underground structures, such that it achieves higher accuracy and efficiency, meanwhile it proves to be convenient for engineering design. To this end, a new model for seismic response analysis of underground structures is proposed. The model is versatile to deal with wave scattering and diffraction by canyons, subsurface cavities, subways and tunnels etc. In case of the presence of complex soil conditions like the layered half-space, a simple and effective technique is developed for the evaluation of Green's functions. Numerical examples are provided to validate the accuracy and efficiency of the proposed approach.