With　the　rapid　development　of　the　economy　in　China,　numerous　CFST　bridges　have　been　built　in　recent　years.　The　CFST　arch　bridges　have　become　a　viable　alternative　to　reinforced　concrete　(RC)　arch　bridges　or　steel　arch　bridges　due　to　several　advantages.　One　of　the　most　important　advantages　is　the　confinement　effect　of　core　concrete　from　steel　tube　under　compression.　However,　this　beneficial　composite　action　will　be　probably　weakened　by　debonding,　which　is　almost　unavoidable　as　a　common　phenomenon　in　CFST　structures.　In　this　paper,　the　finite　element　models　of　debonding　circular　CFST　columns　with　different　slenderness　ratios　were　implemented　using　the　finite　element　software　ABAQUS,　and　the　validity　and　accuracy　of　the　results　were　verified　by　test　results　of　debonding　CFST　stub　columns.　Utilizing　the　finite　element　model,　a　parametric　analysis　was　carried　out　to　study　the　influence　of　the　following　parameters　on　the　ultimate　load　capacity　of　debonding　specimens:　debonding　arc-length　ratio,　debonding　thickness,　confinement　factor　and　slenderness　ratio.　Based　on　the　results　of　parametric　analysis,　a　simplified　calculation　formula　was　proposed　to　calculate　the　ultimate　load　capacity　of　debonding　circular　CFST　columns　subjected　to　axial　load.