The　existing　theoretical　analysis　models　of　concrete-filled　double　skin　tube　(CFDST)　columns　are　limited　to　the　analysis　of　CFDST　columns　with　circular　outer　and　inner　tubes　(CC-CFDST).　The　purpose　of　this　paper　is　to　propose　a　unified　model　for　CFDST　columns　with　different　cross-sectional　shapes,　including　CFDST　columns　with　rectangular　outer　and　inner　tubes　(RR-CFDST),　CFDST　columns　with　square　outer　and　inner　tubes　(SS-CFDST),　CFDST　columns　with　square　outer　and　circular　inner　tubes　(SC-CFDST),　CFDST　columns　with　circular　outer　and　square　inner　tubes　(CS-CFDST),　CC-CFDST　columns.　The　CFDST　columns　with　different　shapes　(original　columns)　are　replaced　with　equivalent　CC-CFDST　columns　by　assuming　that　they　have　the　same　cross-sectional　areas　of　the　inner　and　outer　steel　tubes　and　concrete.　The　difference　in　mechanical　properties　between　the　original　column　and　the　equivalent　column　is　attributed　to　the　difference　in　the　confining　effect　of　the　steel　tube　on　the　core　concrete　caused　by　the　different　shape,　which　is　considered　by　the　shape　effect　coefficient　ke.　The　proposed　model　is　verified　by　collected　experimental　data　of　CFDST　columns　with　different　cross-sectional　shapes.　The　mean　value　and　coefficient　of　variation　of　the　ratio　of　the　calculated　bearing　capacity　to　the　experimental　bearing　capacity　are　1.006　and　0.119,　respectively.　The　results　show　that　the　proposed　model　can　predict　the　axial　compression　bearing　capacity　and　load-deflection　curves　of　CFDST　columns　accurately.