Due　to　the　lower　elastic　modulus,　the　composite　effect　of　concrete-filled　aluminum　alloy　tube　(CFAT)　is　weaker　than　that　of　concrete-filled　steel　tube　(CFST),　resulting　in　different　behaviour　of　CFAT　columns　compared　to　CFST　ones.　However,　so　far,　experimental　study　on　CFAT　columns　is　very　limited,　which　makes　their　mechanical　properties　not　fully　understood.　In　addition,　the　existing　theoretical　models　are　mainly　limited　to　analyze　the　performance　of　CFST　columns　or　FRP-confined　concrete.　However,　there　is　a　lack　of　a　theoretical　model　for　predicting　the　complete　axial　load　versus　axial　strain　response　of　CFAT　under　axial　compression.　To　fully　understand　the　axial　behavior　of　CFAT　columns　and　establish　the　axial　load　versus　axial　strain　theoretical　model,　a　total　of　9　circular　CFAT　short　columns　were　axially　tested.　The　effects　of　concrete　strength,　diameter-to-thickness　ratio　on　the　failure　pattern,　axial　load　versus　deformation　response,　ultimate　capacity,　composite　effect,　and　ductility　of　the　tested　specimens　were　ascertained.　The　test　results　indicate　that　CFAT　short　columns　undergo　bulging　or　shear　failure,　exhibits　good　composite　effect　and　ductility;　As　the　concrete　strength　increases,　the　composite　effect　and　ductility　of　columns　are　decreased,　while　the　ultimate　capacity　is　increased.　In　addition,　based　on　experimental　results,　the　existing　dilation　model　of　confined　concrete　proposed　by　Teng　was　verified.　By　introducing　the　verified　dilation　model,　a　theoretical　model　for　analyzing　the　axial　response　of　CFAT　short　columns　was　proposed　by　use　of　basic　equations　of　elasto-plastic　theory.　By　comparing　with　the　experimental　results　compiled　from　the　current　study　and　previous　literature,　the　compared　results　indicate　that　the　proposed　theoretical　model　is　in　good　agreement　with　the　experimental　results.　©　2024　Elsevier　Ltd