To　improve　the　structural　properties　at　the　connection　region　of　prefabricated　buildings,　ultra-high　performance　concrete　(UHPC)　with　excellent　mechanical　properties　is　used　as　the　permanent　formwork　for　the　connection　region　and　a　composite　member　is　consisted　by　UHPC　permanent　formwork　and　the　core　concrete.To　study　the　axial　compressive　behaviors　of　this　new　assembled　UHPC-RC　composite　columns,　the　axial　compressive　test　of　short　columns　was　carried　out.　The　effects　of　steel　fiber　contents　in　precast　UHPC　panels　and　the　thickness　of　UHPC　panels　on　axial　compressive　performance,including　axial　compressive　bearing　capacity,　ductility　and　energy　absorption　capacity,　were　investigated.　The　results　showed　that　compared　with　normal　strength　concrete　column,　the　axial　compressive　bearing　capacity　of　composite　column　was　increased　by　57%　~　94%,　and　energy　absorption　capacity　was　improved　by　more　than　100%.The　axial　compressive　bearing　capacity,ductility　and　energy　absorption　capacity　of　the　composite　column　with　the　fiber　of　3%　in　the　UHPC　jacket　was　23%,　56%　and　114%　higher　than　that　of　the　composite　column　with　the　fiber　of　2%,that　is,the　increasing　of　the　fiber　content　in　the　UHPC　jacket　from　2%　to　3%,　the　axial　behaviors　of　composite　column　can　significantly　improve.　Based　on　the　test　results,　a　new　model　to　calculate　the　axial　bearing　capacity　of　this　new　UHPC-RC　composite　columns　was　proposed,and　a　reduction　factor　of　the　compressive　strength　of　UHPC　was　given.　©　2024　Editorial　Board　of　Journal　of　Basic　Science　and.　All　rights　reserved.