Abstract: Combining the idea of multiple reflection of travelling waves in a structure with consideration of soil-structure interaction, an analytical solution of horizontal seismic response of multistorey shear-building type is presented. It is shown that the formula, presented by K. Kanai, correlating the motions at the top and base of a structure is still valid when the interaction of soil-structure is considered. This formula is further checked by using the strong earthquake motion records obtained at Beijing Hotel during the Tangshan earthquake of 1976.