Seismic　soil-structure　interaction　(SSI)　of　structure　with　shallow　foundation　is　studied　using　response　spectrum　method　(RSM).　A　SSI　model　is　first　constructed　with　the　consideration　of　the　coupling　of　horizontal　and　rocking　motions　of　structural　foundation.　In　this　model,　the　structure　is　modelled　by　finite　elements　and　the　soil　by　the　accurate　lumped　parameter　model　(LPM)　based　on　rational　approximation.　The　SSI　model　is　a　non-classically　damped　system　due　to　introducing　damping　of　LPM.　Complex　mode　superposition　RSM　is　subsequently　applied　to　solve　the　non-classically　damped　SSI　system　under　design　response　spectrum.　Seismic　responses　of　3-story　and　6-story　shear　structures　on　two　types　of　sites　are　finally　calculated　using　the　SSI　model　and　RSM.　The　numerical　experiments　indicate　that　RSM　can　be　an　effective　tool　to　analyze　seismic　SSI　of　structure　with　shallow　foundation,　and　some　conclusions　are　drawn:　(1)　the　coupling　of　horizontal　and　rocking　motions　of　foundation　should　be　considered　for　relatively　high　structure　on　soft　soil　site,　(2)　the　rational-approximation-based　LPM　is　more　accurate　than　the　simple　one,　(3)　the　over-damped　case　can　be　neglected　in　the　complex　mode　superposition　process　although　it　arises　at　fundamental　frequency,　and　(4)　the　quasi　spectrum　transform　relationship　can　be　used　to　obtain　the　relative　displacement　and　relative　velocity　response　spectra　from　the　given　absolute　acceleration　design　response　spectrum.