In　structures　of　earthquake-prone　zones,　round-ended　concrete-filled　steel　tubular　(RCFST)　columns　have　been　utilised.　Hysteretic　testing　on　12　RCFST　columns　was　conducted　to　investigate　the　effects　of　the　axial　load　ratio　and　height-width　ratio　on　their　seismic　behaviour.　The　test　results　showed　that　compared　to　concrete-filled　rectangular　steel　tubular　(CFRST)　columns,　RCFST　columns　experienced　more　moderate　damage　while　possessing　a　plumper　cyclic　curve　with　larger　ductility,　deformation　capacities,　and　energy　dissipation　capabilities.　The　strength,　stiffness,　and　energy　dissipation　capabilities　of　RCFSTs　all　increased　with　the　increase　of　height-width　ratio,　but　the　ductility　decrease　with　the　increase　of　the　ratio.　By　contrast,　the　height-width　ratio　has　a　negligible　effect　on　the　equivalent　damping　coefficient　and　the　rate　of　stiffness　degradation.　Finite　element　(FE)　models　were　developed　for　the　tested　RCFST　columns,　and　the　FE　envelope　curves　are　in　good　agreement　with　the　test　results.　Based　on　the　FE　model,　a　parametric　study　of　the　envelope　curve　of　RCFST　columns　was　carried　out.　The　main　parameters　included　the　material　strength,　steel　ratio,　slenderness　ratio,　axial　load　ratio　and　height-width　ratio.　According　to　the　parametric　study,　the　increase　of　height-to-width　ratio　leads　to　an　increase　in　strength　and　stiffness　but　a　decrease　of　ductility.　When　the　yield　strength　of　the　steel　increases　from　235　MPa　to　700　MPa,　the　bearing　capacity　increases　by　89.　1%　.　As　the　steel　ratio　is　enhanced　from　0.　05　to　0.　2,　the　bearing　capacity　increase　by　146%　.　When　the　slenderness　ratio　is　improved　from　20　to　100,　the　bearing　capacity　decreases　by　88.　3%　.　As　the　axial　compression　ratio　is　changed　from　0.　01　to　0.　8,　the　bearing　capacity　is　reduced　by　61.　2%　.　When　the　height-to-width　ratio　is　increased　from　1　to　3,　the　bearing　capacity　increases　215.　3%　.　Based　on　the　restoring　force　model　of　concrete-filled　circular　steel　tubular　columns,　a　restoring　force　model　of　the　RCFST　columns　was　proposed.　The　predicted　results　using　the　restoring　force　model　were　in　good　agreement　with　the　test　results,with　an　error　less　than　10%　.　©　2023　Science　Press.　All　rights　reserved.