A　new　composite　structure　composed　of　corrugated　steel　webs　(CSW),　double　concrete　filled　steel　tubular　chords　(CFST)　and　concrete　slabs　(CS)　was　presented.　To　understand　the　flexural　behaviors　under　positive　and　negative　bending　moments,　the　experiments　of　new　composite　continuous　box-girder　were　carried　out,　and　the　failure　modes　and　deflection　patterns　of　the　girder,　and　the　development　rules　of　concrete　plate　cracks　were　studied.　According　to　the　test　results,　the　calculation　methods　of　deformation　and　bearing　capacity　of　the　new　type　of　composite　girder　were　put　forward　and　verified.　Experimental　result　shows　the　strain　peak　values　of　mid-span　and　intermediate　support　are　only　3.7%　and　5.1%　of　the　value　of　bottom　steel　concrete　pipe　chord　respectively,　therefore　the　longitudinal　strains　of　corrugated　steel　webs　are　small　and　negligible　in　the　positive　and　negative　bending　moment　areas.　The　longitudinal　strains　linearly　change　along　the　height　of　cross　section,　thus　the　plane　cross-section　assumption　can　be　applied　in　the　composite　girder.　Moreover,　the　top　concrete　flange　and　the　bottom　steel　concrete　pipe　chord　bear　load　together.　When　the　cracking　load　is　140　kN,　the　calculated　and　experimental　deflection　are　5.8　mm　and　5.5　mm,　respectively,　and　the　relative　error　is　about　5%.　When　the　load　of　mid-span　cross　section　of　test　beam　reaches　the　ultimate　flexural　capacity,　the　theoretical　and　experimental　load　are　399　kN　and　415　kN,　respectively,　the　experimental　value　is　slightly　higher　than　the　calculated　value,　but　the　error　is　very　small　and　about　4%,　so　the　theoretical　calculation　methods　of　deflection　and　flexural　capacity　of　composite　beam　are　simple　and　reliable.　©　2016,　Editorial　Department　of　Journal　of　Traffic　and　Transportation　Engineering.　All　right　reserved.