A　total　of　17　tests　of　concrete-filled　round-end　steel　tubular　stub　columns　under　axial　compression　were　carried　out　with　different　sectional　aspect　ratios,　steel　ratios　and　the　structural　measures.　The　failure　characteristics　and　the　behavior　of　the　composite　column　under　axial　compressive　load　were　exhibited.　It　can　be　found　from　experiments　that　core　concrete　can　be　confined　by　the　steel　tube.　The　local　buckling　can　be　avoided　by　the　longitudinal　diaphragm　or　the　binding　bar.　The　longitudinal　diaphragm　or　the　binding　bar　can　be　used　to　improve　the　strength　and　ductility.　For　strength,　the　binding　bar　is　better　than　the　longitudinal　diaphragm.　But　for　ductility,　the　reverse　is　true.　The　finite　element　(FE)　soft　ABAQUS　was　used　to　analyze　the　behavior　of　concrete-filled　round-end　steel　tubular　stub　columns.　The　FE　results　agree　well　with　experimental　ones.　Based　on　existing　simplified　strength　models　of　the　concrete-filled　rectangular　steel　tubular　stub　column　under　axial　compression,　a　simplified　strength　model　was　proposed　to　predict　the　load　carrying-capacity　of　concrete-filled　round-end　steel　tubular　stub　columns　with　the　longitudinal　diaphragm　under　axial　compression.　In　addition,　the　longitudinal　diaphragm　or　the　binding　bar　is　suggested　to　be　applied　when　the　width　to　thickness　ratio　of　the　flat　of　the　steel　tube　is　more　than　60.