To　investigate　the　effects　of　non-conservative　forces　on　the　out-of-plane　stability　of　concrete　filled　steel　tubular　(CFST)　X-type　arches,　the　structural　spatial　mechanical　behaviors　of　CFST　X-type　arches　were　analyzed　via　experiment　and　finite　element　analysis.　Based　on　a　prototype　bridge,　the　structural　spatial　mechanical　behaviors　of　a　CFST　X-type　arch　with　hangers　were　tested　to　elucidate　the　failure　mechanisms　of　the　arch　model.　A　finite　element　model　of　a　standard　CFST　X-type　arche　was　created　based　on　the　experimental　data　and　the　actual　structural　engineering　parameters.　The　conservative　and　non-conservative　forces　from　hangers　were　considered　respectively　in　models　with　or　without　tie　hangers.　The　effects　of　arch　rib　inclination,　rise-span　ratio,　and　width-span　ratio　on　the　out-of-plane　ultimate　bearing　capacities　of　CFST　X-type　arches　considering　the　non-conservative　force　from　hangers　or　not　were　analyzed.　Based　on　a　finite　element　model　for　combined　material　and　geometric　nonlinearities　and　in　terms　of　load　and　displacement　ratios,　the　improvement　in　the　spatial　mechanical　behaviors　of　arch　rib　due　to　the　non-conservative　force　was　quantitatively　analyzed　under　different　parameters.　Research　results　indicate　that　during　the　spatial　mechanical　process,　the　displacement　of　the　CFST　X-type　arch　is　symmetrically　distributed　about　the　crown　section,　and　the　strain　distribution　is　also　highly　symmetric.　Therefore,　the　arch　model　has　good　overall　stability　and　low　sensitivity　to　initial　geometric　defects　during　the　spatial　mechanical　process.　The　arch　model　ultimately　failed　due　to　an　out-of-plane　extreme　point　instability.　The　arch　rib　mainly　bears　compression　and　out-of-plane　bending　moment,　and　the　out-of-plane　bending　moment　is　the　main　controlling　factor　for　the　stability　and　ultimate　bearing　capacity　of　the　arch　model.　The　out-of-plane　ultimate　bearing　capacity　of　CFST　X-type　arches　initially　increases　and　then　decreases　with　the　increasing　arch　rib　inclination,　rise-span　ratio,　and　width-span　ratio.　The　arch　model　reaches　its　maximum　ultimate　bearing　capacity　when　the　arch　rib　inclination　is　9°,　the　rise-span　ratio　is　0.25,　and　the　width-span　ratio　is　0.03.　The　non-conservative　force　should　be　considered　when　calculating　the　out-of-plane　ultimate　bearing　capacity　of　CFST　X-type　arches,　as　the　omission　of　the　force　will　lead　to　a　22%　underestimation　of　the　out-of-plane　ultimate　bearing　capacity.　©　2022,　Editorial　Department　of　Journal　of　Traffic　and　Transportation　Engineering.　All　right　reserved.