Low-frequency　excitation　experiment　of　a　1:4　scaled　steel　frame　model　was　performed　in　an　indoor　soil　bin.　Using　an　exciter　which　can　output　different　seismic　waves　to　excite　the　steel　frame,　vibration　picking　devices　were　used　to　measure　the　acceleration　and　displacement　responses　of　floors.　By　spectral　analysis　the　fundamental　frequency　and　natural　period　of　the　model　were　obtained,　and　the　shock　absorption　coefficient　was　calculated.　Using　SAP2000　to　simulate　the　model　on　rigid　foundation,　the　same　seismic　waves　were　input　on　the　model　to　calculate　the　fundamental　frequency,　natural　period,　peak　acceleration　and　displacement　of　the　top　floor　of　the　model.　Compared　with　the　results　of　experiment,　several　conclusions　are　drawn.　After　considering　soil-structure　interaction,　natural　period　of　the　model　is　elongated.　With　the　same　stiffness,　the　greater　the　mass　of　the　floor　is,　the　more　obvious　the　elongation　effect　is.　The　peak　displacement　of　top　floor　increases,　while　the　peak　acceleration　decreases.　Curves　of　displacement　amplification　and　acceleration　reduction　coefficients　versus　structural　stiffness　were　drawn.　It　is　found　that　the　displacement　amplification　and　acceleration　reduction　coefficients　vary　in　accordance　with　√k/m,　which　can　be　defined　by　two　fitted　curves　obtained　by　regression　analysis.　The　curves　can　be　referred　in　practical　seismic　design.