The　response　spectrum　method　(RSM)　has　been　incorporated　into　many　codes　for　seismic　design　of　aboveground　structures　since　1950s.　However,　no　RSM　is　presented　in　details　for　the　seismic　design　of　underground　structures　due　to　the　complexity　of　seismic　soil-structure　interaction　(SSI).　In　this　paper,　the　RSM　is　developed　for　the　seismic　analysis　of　the　underground　structures　including　SSI.　First,　the　underground　design　response　spectrum　is　derived　using　two　different　procedures　from　the　ground　design　response　spectrum　that　is　commonly　available　in　most　seismic　design　codes.　Second,　the　SSI　analysis　model　consisting　of　the　underground　structure　and　its　adjacent　soil　is　established　with　the　roller　side　boundaries　and　the　bottom　boundary　subjected　to　the　underground　response　spectrum.　Third,　the　RSM　is　applied　to　the　SSI　analysis　model　to　estimate　the　structural　response　under　the　underground　response　spectrum.　Finally,　the　numerical　examples　are　presented　to　demonstrate　the　feasibility　of　the　RSM　for　the　SSI　analysis　model　of　underground　structure.