The　structural　dynamic　response　of　a　ten-floor　building　is　calculated　and　compared　using　time-history　analysis,　modal　superposition　and　wavelet　transform.　Three　results　are　consistent　completely　and　the　uniqueness　of　structural　dynamic　response　for　linear　timeinvariant　system　is　verified.　Time-history　analysis　can　be　used　in　nonlinear　system,　while　model　superposition　can　only　be　applied　to　linear　system.　Wavelet　transform　can　be　adopted　in　nonlinear　system　as　well　as　in　calculating　multi-resolution　energy　spectrum.　It　develops　seismic　analysis　from　traditional　model　of　hysteretic　energy　to　a　system　for　structural　damage　and　ductility　estimate.