An　experimental　investigation　was　conducted　on　CFRP　reinforced　concrete-filled　stainless　steel　circular　hollow　section　(CHS)　tubes　subjected　to　in-plane　bending.　A　total　of　36　specimens　including　concrete-filled　stainless　steel　CHS　tubes　and　CFRP　reinforced　concrete-filled　stainless　steel　CHS　tubes　were　tested.　An　extensive　parametric　study　was　carried　out　by　using　the　verified　finite　element　model　to　investigate　the　strengthening　effect　of　CFRP　on　the　flexural　behaviour　of　concrete-filled　stainless　steel　CHS　tubes.　It　is　shown　from　the　comparison　that　the　strengthening　effect　of　CFRP　improved　with　the　increase　of　the　strength　ratio　(beta)　of　CFRP.　Furthermore,　the　ultimate　strength　was　enhanced　proportionally　with　the　increase　of　the　layers　of　CFRP　positioned　in　the　longitudinal　direction　for　reinforcement,　but　the　ductility　generally　deteriorated.　Finally,　the　flexural　strength　and　flexural　stiffness　of　concrete-filled　stainless　steel　CHS　tubes　is　improved　by　increasing　the　interface　friction　coefficient　between　stainless　steel　tubes　and　concrete　up　to　0.6.