This　paper　studies　experimentally　the　structural　behavior　of　channel　steel　reinforced　concrete-filled　glass　fiber-reinforced　polymer　(GFRP)　tubular　stub　columns.　To　understand　their　structural　performance,　we　examined　27　specimens　which　subjected　to　axial　compression.　The　variables　of　the　specimen　are　concrete　strength　grade,　diameter-to-thickness　ratio　of　GFRP　tube　and　steel　ratio.　The　displacement-load　curve,　strain-load　curve,　ultimate　load,　axial　compressive　stiffness　and　failure　characteristics　of　the　specimens　were　analyzed.　The　results　of　the　test　show　that　the　specimens’　ultimate　bearing　capacity　increases　as　the　concrete　strength　increases.　And　those　specimens　with　higher　concrete　strength　grade　have　greater　initial　stiffness　and　better　deformation　capacity　than　those　with　lower　concrete　strength　grade.　The　varieties　of　the　steel　ratio　have　no　significant　effect　on　the　specimens’　axial　deformation　property.　The　confinement　coefficient　is　proposed　to　evaluate　the　constraint　effect　of　the　GFRP　tube　on　both　the　inner　channel　steel　and　the　core　concrete.　There　was　a　negative　correlation　between　the　restraint　effect　and　the　diameter-thickness　ratio　of　the　GFRP　tube.　A　simplified　formula　for　calculating　the　axial　bearing　capacity　of　the　composite　columns　is　proposed.　©　2019　Elsevier　Ltd