Based on an analysis made of the soil-structure interaction coefficient method and the response displacement method applied to the seismic analysis of underground structures, an improved response displacement method of deformation modification has thus been proposed, with the advantages of the former two methods integrated. The improved response displacement method, which is based on the traditional response of the displacement method, makes an modification of the structural deformation of the reaction displacement method by the deformation of the soil-structural interaction coefficient method, thus adjusting the internal force of the structure and reducing the error of the traditional response displacement method. In order to verify the effectiveness of the improved method, a comparative calculation has been made between the traditional response displacement, the improved response displacement method and the dynamic analysis method by altering the dimension of the structure, the stiffness of the soil and the depth of the structure. The results show that: the overall calculation results of the improved response displacement method are more favorable than the conventional response displacement method; the improved response displacement method can generally enlarge or reduce the result from the traditional response displacement method, but cannot change the distribution form of the internal force of structures; there still exists considerable errors in the traditional response displacement method.