The　compressive　behavior　of　steel　tube　reinforced　concrete　(STRC)　columns　under　eccentric　loads　was　investigated　experimentally　and　numerically　in　this　paper.　Primary　parameters　included　the　eccentricity　ratio,　the　concrete-filled　steel　tube　(CFST)　area　ratio,　and　the　longitudinal　rebar　ratio.　This　paper　analyzed　the　impacts　of　these　parameters　as　well　as　the　failure　modes,　the　full-range　compression　process,　and　the　strain　development.　Similar　to　the　reinforced　concrete　(RC)　column,　the　full-range　compression　process　of　STRC　column　under　eccentric　loads　can　be　divided　into　three　stages,　i.e.,　elastic　stage,　elastic-plastic　stage　(cracking　stage),　and　plastic　stage　(descent　stage).　The　experimental　findings　showed　that,　on　the　near-load　side　of　the　STRC　column,　the　outer　concrete　crushed,　and　the　longitudinal　rebars　buckled　in　compression.　Conversely,　on　the　far-load　side,　the　concrete　exhibited　cracking　in　tension,　and　the　longitudinal　rebars　exhibited　tension.　Finite　element　(FE)　analysis　results　demonstrated　that,　similar　to　a　RC　column,　three　distinct　failure　mechanisms　can　be　identified　for　STRC　columns　under　eccentric　loads,　i.e.,　compression-controlled,　balanced,　and　tension-controlled　failures.　During　the　compression　process,　analyses　were　conducted　on　the　contact　stress　between　the　steel　tube　and　concrete,　as　well　as　on　the　load　distribution　between　the　inner　CFST　and　the　outer　RC.　The　ultimate　load　of　the　STRC　column　decreased　with　an　increase　in　the　eccentricity　ratio,　while　it　increased　with　larger　longitudinal　rebar　ratio　and　CFST　area　ratio.　Based　on　the　experimental　and　FE　analysis　results,　a　simplified　calculation　method　was　developed　to　determine　the　eccentricity　reduction　coefficient　for　STRC　columns.　©　2023