For　dumbbell-shaped　concrete-filled　steel　tubular　(CFST)　arches,　out-of-plane　instability　is　one　of　the　prominent　issues.　In　this　paper,　an　experimental　study　on　the　out-of-plane　stability　of　dumbbell-shaped　section　CFST　arches　under　spatial　loads　was　carried　out　and　the　entire　test　process　was　analyzed　in　detail.　The　relationship　between　the　loads　and　displacements　were　obtained　and　the　experimental　phenomena　as　well　as　the　out-of-plane　instability　patterns　were　depicted.　The　experimental　results　indicate　that　the　lateral　displacement　is　larger　than　the　vertical　one　during　the　entire　experimental　process.　And　the　characteristics　of　the　out-of-plane　nonlinear　deformation　are　clearly　identified.　The　failure　mode　clearly　shows　the　superior　elastoplasticity　and　ductility　of　the　arch　model.　The　horizontal　force　highly　affects　the　lateral　stability　of　the　arch.　Through　comparison,　the　out-of-plane　bearing　capability　of　the　dumbbell-shaped　concrete　filled　steel　tubular　arch　is　considerably　lower　than　the　in-plane　ultimate　bearing　capacity　under　the　same　load.