In　order　to　study　the　influence　of　concrete　strength　and　steel　ratio　on　the　axial　compressive　bearing　capacity　of　a　rectangular　steel　tube　confined　ultra-high-strength　concrete　short　columns,　and　to　evaluate　the　applicability　of　current　bearing　capacity　calculation　methods,　a　validated　finite　element　model　is　used　to　calculate　the　ultimate　bearing　capacity　of　rectangular　steel　tube　confined　concrete　short　columns　under　axial　compression　for　parameter　study.　The　accuracy　of　the　current　calculation　methods　is　evaluated　by　comparing　the　calculation　results　with　test　data,　and　the　calculation　method　of　bearing　capacity　is　improved.　The　study　shows　that　with　the　increase　of　concrete　strength,　the　confining　action　tends　to　decrease　with　the　same　confining　force　parameters.　The　confining　action　of　high-strength　concrete　members　is　less　affected　by　steel　ratio　and　chamfer　ratio.　The　confining　action　of　short　rectangular　steel　tube　columns　decreases　with　the　increase　of　the　length　ratio　of　long　and　short　sides.　Due　to　the　decrease　of　confining　action　with　increasing　concrete　strength　and　the　materials　strength　exceeds　the　limitation,　the　proposed　formula　can　make　a　better　prediction　on　the　ultimate　bearing　capacity　than　current　calculation　method.　©　2022,　Progress　in　Steel　Buiding　Structures　All　right　reserved.