In　order　to　quantitatively　evaluate　the　shear-bearing　capacity　of　shear　connectors　of　square　concrete　filled　steel　tube　(CFST),　push-out　tests　on　14　square　CFSTs　with　shear　connectors　have　been　carried　out.　Among　the　14　CFSTs,　there　are　13　specimens　with　steel　plate　connectors　and　one　specimen　with　steel　bar　connectors.　The　following　factors　are　investigated　to　figure　out　their　influences　on　the　performance　of　CFSTs,　which　are　the　width　to　thickness　ratio　of　steel　tube,　thickness　of　steel　plate,　length　of　steel　plate,　strength　of　concrete,　welding　condition　of　steel　plate,　number　of　steel　plate　layer　and　interlayer　spacing.　The　test　results　show　that　the　ultimate　bearing　capacity　and　the　elastic　stiffness　increase　with　decreasing　width　to　thickness　ratio　of　the　steel　tube,　and　increasing　thickness　and　length　of　the　steel　plate.　With　increasing　concrete　strength,　the　ultimate　bearing　capacity　also　increases.　However,　the　welding　condition　has　no　effect　on　the　ultimate　bearing　capacity.　The　ultimate　bearing　capacity　of　the　CFST　with　double-layer　steel　plate　is　greater　than　that　with　single-layer　steel　plate.　The　ultimate　bearing　capacity　of　steel　bar　type　shear　connector　is　87%　greater　than　that　of　the　steel　plate　type　shear　connector,　and　the　steel　bar　specimen　shows　good　ductility.　A　formula　for　calculating　the　shear-bearing　capacity　of　shear　connectors　has　been　developed,　and　the　calculated　shear-bearing　capacities　are　in　good　agreement　with　the　test　data.