Fourteen　specimens　were　tested　under　axial　compression　to　investigate　the　behavior　of　concrete-filled　stiffened　square　steel　tubular　stub　columns.　The　stiffening　effect　was　achieved　by　welding　longitudinal　stiffeners　on　the　inside　surfaces　of　the　steel　tubes.　The　main　parameters　varied　in　the　test　were　width-thickness　ratio　of　the　steel　tube　and　depth-thickness　ratio　of　the　stiffener.　The　load-deformation　relationship　curves　of　concrete-filled　stiffened　square　steel　tubular　stub　columns　subjected　to　axial　compression　were　analyzed　using　the　finite　element　software　ABAQUS.　The　analysis　results　were　in　good　agreement　with　test　results.　On　the　basis　of　the　experimentally　verified　reliability　of　the　finite　element　model,　mechanical　behavior　of　the　concrete-filled　square　steel　tubular　stub　columns　without　reinforcing　rib,　with　one　reinforcing　rib　and　with　two　reinforcing　ribs　were　analyzed　respectively　and　compared　in　terms　of　stress　versus　strain　relationship　curves,　longitudinal　stress　distributions　of　steel　tube　and　core　concrete,　and　their　interaction.　The　analysis　results　show　that　using　stiffeners　can　result　in　the　increas　of　maximum　axial　stress　of　core　concrete　and　the　tensile　stress　areas　of　steel　tubes　are　decreased　as　a　result　of　the　welding　stiffeners.　The　stability　of　steel　tube　is　also　improved.　The　confinement　effect　of　concrete-filled　stiffened　square　steel　tubular　stub　columns　is　mainly　developed　at　steel　tube　corners　and　the　places　where　stiffeners　were　welded.　And　the　confinement　effect　on　steel　tube　corners　can　be　enhanced　with　increased　number　of　stiffeners.