The　simplified　algorithm　for　out-of-plane　ultimate　load-carrying　capacity　of　concrete-filled　steel　tubular　(CFST)　solid-rib　arches　under　uniform　vertical　load　was　studied.　The　experimentally　validated　finite　element　model　was　developed.　The　out-of-plane　equivalent　length　coefficients　of　solid-rib　arches　were　obtained　using　out-of-plane　elastic　eigenvalue　buckling　analysis.　Then　the　out-of-plane　elastic　stability　coefficient　was　plotted　against　the　normalized　slenderness　ratio,　and　the　out-of-plane　eigenvalue　buckling　load　or　elastic　buckling　capability　of　arches　was　calculated.　Lastly　effects　of　different　parameters　on　the　out-of-plane　ultimate　load-carrying　capacity　of　CFST　solid-rib　arches　were　determined　using　geometric　and　material　nonlinear　finite　element　analysis,　and　a　simplified　algorithm　was　established　by　fitting　the　out-of-plane　elastic-plastic　stability　coefficient　and　normalized　slenderness　ratio　using　Perry-Robertson　formula.　Ratio　of　the　elastic　stability　coefficient　to　the　elastic-plastic　counterpart　was　plotted　against　the　out-of-plane　normalized　slenderness　ratio,　from　which　the　out-of-plane　elastic-plastic　ultimate　load-carrying　capacity　was　determined　according　to　the　corresponding　elastic　buckling　load.　Results　show　that　the　proposed　simplified　algorithm　can　accurately　predict　the　out-of-plane　eigenvalue　buckling　load　and　the　elastic-plastic　ultimate　load-carrying　capacity　of　the　CFST　solid-rib　arches.　Copyright　©　2015　Editorial　Department　of　Journal　of　Donghua　University.　All　rights　reserved.