10　concrete-filled　steel　tubular　(CFST)　dumbbell　shaped　columns　under　concentric　loads　are　tested.　The　distance　between　two　tubes　and　the　distance　between　two　webs　with　or　without　tie　rod　to　connect　the　two　webs　are　taken　as　experimental　parameters.　The　load-displacement　relations　and　the　failure　mechanisms　of　the　specimens,　the　load-strain　relations　of　both　circular　steel　tubes　and　steel　webs,　and　the　load-Poisson＇s　ratio　relation　of　the　composite　material　are　analyzed.　Experiment　results　indicate　that　the　property　of　the　circular　CFST　in　the　dumbbell　shaped　member　is　the　same　as　a　concentrically-loaded　CFST　single　tubular　column.　The　concrete　inside　the　web　space　is　also　constrained　by　the　link　steels.　The　rupture　of　welding　seam　connecting　the　web　plates　and　the　steel　tube　is　the　most　pronounced　failure　mechanism.　A　simple　calculation　method　for　the　ultimate　load　of　dumbbell　shaped　CFST　concentrically-loaded　columns　is　proposed.