In　order　to　study　the　mechanism　of　the　I-sectional　concrete　filled　steel　tube　(CFST)　column　subjected　to　compression-bending　load　and　further　determine　its　aseismic　performance　index,　a　bottom　strengthened　I-sectional　CFST　column　was　proposed,　whose　flanges　close　to　the　bottom　of　the　column　were　welded　with　enhancing　steel　plates.　Based　on　the　experimental　results,　the　factors　affecting　the　load-bearing　capacity　were　analyzed.　By　means　of　finite　element　analysis　software　ABAQUS,　the　analysis　to　simulate　numerically　the　specimens　with　different　compression　ratios,　different　strength　grades　of　concrete,　different　heights　and　thickness　of　bottom　strengthened　steel　plates　were　carried　out.　The　analytical　results　were　compared　with　the　experimental　results.　The　study　shows　that:　the　load-bearing　capacity　and　the　ductility　decrease　when　the　axial　compression　ratio　increases;　the　bearing　capacity　also　increases　with　the　strength　grade　of　concrete,　but　its　decline　gradient　steepens　and　the　ductility　decreases;　when　the　height　of　the　strengthened　plate　increases,　the　load-bearing　capacity　of　specimens　increases　steadily,　the　energy　dissipation　capacity　increases,　and　the　ductility　is　approximately　equal　to　each　other;　when　the　thickness　of　the　strengthened　plate　increases,　the　load-bearing　capacity　improves　only　slightly.　The　I-sectional　concrete　filled　steel　tube　column　with　bottom　enhancing　plates　shows　a　better　aseismic　performance　and　higher　energy　dissipation　capacity　if　suitable　constructional　requirements　are　satisfied.　Such　structural　configuration　can　be　adopted　in　the　design　of　high-rise　buildings.　©,　2015,　Tsinghua　University.　All　right　reserved.