Although　a　number　of　investigation　on　seismic　behavior　of　concrete-filled　steel　tubular　(CFST)　frame　were　carried　out,　few　investigations　have　been　reported　on　the　seismic　behavior　of　CFST　frame　considering　SSI.　Modal　analysis　and　seismic　behavior　of　a　4-storey　CFST　frame　were　investigated　by　software　Ansys　in　this　paper.　Stiffness　of　soil　mass　solved　from　Mindlin　formula　and　mass-damping　element　to　simulate　soil　mass　were　employed　to　reduce　the　structural　mode　of　the　frame　so　as　to　decrease　the　running　time.　The　modal　test　results　in　laboratory　shows　that　natural　frequencies　decrease　whilst　periods　increase　considering　SSI.　Three　earthquake　wave　records　were　used　to　analyze　the　seismic　responses　of　both　rigid　and　SSI　frames.　The　simulation　shows　that　the　translation　deformation　and　torsional　deformation　one　considering　SSI　increase　from　12　to　62.75　percent.　As　a　result,　SSI　should　be　appropriately　considered　in　the　seismic　design　due　to　the　effect　of　SSI　on　the　seismic　responses　to　some　extent.