RU-NC　column　is　a　new　type　of　composite　structurewhich　is　composed　of　reinforced　ultra-high　performance　concreteRUtube　and　normal　concreteNCcore　column.　In　order　to　investigate　the　axial　compression　performance　and　the　bearing　capacity　calculation　method　of　RU-NC　composite　short　columnsthe　axial　compression　test　was　carried　out　considering　the　experimental　parametersincluding　wall　thickness　of　UHPC　tubestirrup　spacing　and　steel　fiber　volume　fraction.　While　a　comparative　test　of　U-RC　composite　short　columns　composed　of　ultrahigh　performance　concreteUtube　and　reinforced　concreteRCcore　column　reinforced　with　spiral　stirrups　was　carried　out.　Thereforenumerical　analysis　was　carried　out　based　on　the　finite　element　modes　established　on　ABAQUS　software.　The　results　show　that　the　whole　compression　process　of　RU-NC　composite　short　column　could　be　divided　into　elastic　stagecrack　working　stage　and　steel　yield　stage.　Both　RU　tube　and　spiral　stirrups　have　a　certain　constraint　effect　on　the　core　concrete.　The　failure　mode　of　composite　column　is　characterized　by　that　the　RU　tube　and　the　concrete　core　were　crushedand　the　spiral　stirrups　were　broken　at　the　same　time.　Compared　with　U-RC　composite　short　columnRU-NC　composite　short　column　with　steel　cages　moving　from　core　concrete　to　UHPC　tube　has　better　crack　resistanceductility　and　higher　ultimate　bearing　capacity.　The　bearing　capacity　of　RU-NC　composite　short　column　increases　linearly　with　the　increment　of　UHPC　tube　wall　thickness　and　UHPC　tensile　strengthand　shows　a　nonlinear　trend　with　the　decrease　of　stirrup　spacing.　The　ultimate　bearing　capacity　of　RU-NC　composite　short　column　cannot　be　accurately　calculated　by　using　the　current　code　and　the　existing　literature　algorithm.　Based　on　the　theoretical　analysis　of　RU　tube　confined　concretethe　axial　compression　bearing　capacity　algorithm　of　composite　short　column　is　proposed.　The　mean　value　of　the　ratio　of　the　calculated　value　to　the　test　results　is　0.984and　the　varince　is　0.005　3showing　high　accuracywhich　can　lay　a　foundation　for　the　design　and　application　of　the　new　composite　structure　in　the　future.　©　2022　Hunan　University.　All　rights　reserved.