The　flexural　behavior　of　CFRP-strengthened　circular　concrete　filled　steel　tubular　(CFRP-C-CFST)　members　was　investigated　experimentally　and　theoretically.　A　total　of　nine　specimens　were　tested　through　four-point　bending　method,　including　a　comparative　CFST　specimen　without　CFRP　strengthening　(C-CFST),　and　eight　CFRP-C-CFST　specimens.　Based　on　experimental　results,　the　effects　of　different　CFRP　wrapping　length,　number　of　CFRP　layers　and　wrapping　schemes　on　the　flexural　behavior　of　the　CFRP-C-CFST　specimens　are　analyzed.　Two　failure　modes,　including　CFRP　debonding　and　CFRP　fracture,　are　observed　from　the　tested　CFRP-C-CFST　specimens.　Increasing　the　length　of　CFRP　delays　debonding,　while　increasing　the　number　of　CFRP　layers　causes　debonding　to　occur　earlier.　The　flexural　capacity　of　CFRP-C-CFST　specimens　with　two-four　CFRP　layers　is　increased　by　about　20%-70%　compared　to　the　C-CFST　specimens.　A　theoretical　model　based　on　fiber　element　method　is　proposed.　This　model　considers　the　bi-directional　stress　state　of　the　steel　tube　and　the　effect　of　bending　moment　on　the　confinement　factor.　A　representative　test　result　is　selected　to　calibrate　the　distribution　law　of　the　confinement　factor,　and　all　the　test　results　are　predicted　based　on　the　calibrated　parameters.　The　comparison　between　the　predicted　and　the　test　results　shows　that　the　fiber　element　model　can　simulate　the　bending　moment-deflection　curves　of　C-CFST　and　CFRP-C-CFST　members,　and　hence　it　can　predict　the　flexural　capacity,　stiffness　and　ductility　accurately.　©　2023　Institution　of　Structural　Engineers