To　study　the　flexural　behavior　of　prestressed　concrete　(PC)　composite　girder　bridge　with　truss　webs,　the　model　test　of　PC　composite　girder　bridge　with　truss　webs　for　the　flexural　behavior　was　conducted.　To　acquire　the　failure　mode　of　PC　composite　girder　bridge　with　truss　webs,　the　changed　rule　of　the　strain　in　the　bottom　and　top　slab,　and　the　deflection　of　the　girder　of　PC　composite　girder　bridge　with　truss　webs　with　the　variation　of　the　load　were　studied.　Meanwhile,　the　distribution　rule　of　bending　strain　along　the　height　of　the　section　was　revealed.　The　influence　of　height-span　ratio,　and　unbalance　loaded　on　the　flexural　behavior　of　PC　composite　girder　bridge　with　truss　webs　was　analyzed,　and　the　calculation　method　for　the　cracking　bent　moment,　the　bent　moment　in　the　stage　of　the　rebar　yield,　and　ultimate　bent　moment　of　PC　composite　girder　bridge　with　truss　webs　were　put　forward.　The　research　result　shows　that　the　failure　process　of　PC　composite　girder　bridge　with　truss　webs　includes　the　elastic　stage,　cracking　elastic　stage,　elastic-plastic　stage,　and　failure　stage.　In　the　elastic　stage　and　cracking　elastic　stage,　the　deflection　of　the　bottom　and　top　slab　of　PC　composite　girder　bridge　with　truss　webs　met　the　plane-section　assumption.　During　the　loading　process,　there　is　no　joint　failure　and　local　buckling　failure　of　the　truss　web　in　the　PC　composite　girder　bridge　with　truss　webs,　Finally,　the　composite　beam　fails　due　to　excessive　deformation,　and　the　overall　mechanical　performance　is　good.　When　the　height-to-span　ratio　is　between　1/16.25　and　1/9.00,　the　deflection　and　stress　in　the　mid-span　section　of　PC　composite　girder　bridge　with　truss　webs　decrease　with　the　increase　of　height-span　ratio.　When　the　ratio　of　height　to　span　is　greater　than　1/11.50,　the　decreasing　trend　of　deformation　and　stress　in　the　mid-span　section　becomes　slow.　Since　the　PC　composite　girder　bridge　with　truss　webs　had　a　lesser　dead　load,　the　unbalance　loaded　had　a　significant　influence　on　the　deflection　and　stress　of　the　composite　girder,　and　the　magnification　factors　of　the　deflection　and　stress　increased　with　the　increase　of　height-span　ratio.　When　considering　the　dead　load　effect　of　the　main　beam,　the　deformation　and　stress　increase　coefficients　are　1.0831.231　and　1.0741.178,　respectively.　Compared　with　the　results　of　finite　element　analysis　and　test,　the　calculation　methods　of　the　cracking　moment,　reinforcement　yield　moment　and　ultimate　moment　of　PC　composite　beams　with　steel　truss　web　presented　in　this　paper　have　high　accuracy.　©　2022　Editorial　Department　of　Journal　of　Sichuan　University.　All　rights　reserved.