The　buckling　characteristics　of　parabolic　steel　tubular　arch　with　and　without　initial　crookedness　are　investigated　analytically　by　the　dual-nonlinearity　finite　element　method,　when　the　arch　is　subjected　to　a　concentrated　load　at　crown　or　an　unsymmetrical　distributed　load.　The　equivalent　beam-column　method,　in　which　the　basic　equation　of　axial-bending-moment　relationship　in　GB50017-2003　and　the　buckling　factor　considering　influence　of　rise-to-span　and　a　reduction　factor　considering　the　effect　of　initial　crookedness　are　used,　is　presented　for　estimating　critical　load　of　steel　tubular　arch　under　compression　and　bending.　The　calculation　results　by　the　presented　equivalent　beam-column　method　are　accord　with　the　results　by　finite　element　method,　and　this　method　can　be　easily　and　accurately　used　for　estimating　the　critical　loads　of　parabolic　steel　tubular　arch　under　compression　and　bending.