Based　on　the　trial　design　of　the　actual　continuous　prestressed　concrete　jointless　bridge　structure，the　new　type　of　integral　jointless　bridge　with　arch　structure　behind　abutment　was　proposed.　The　three-dimensional　beam-truss　calculation　model　and　the　solid　finite　element　model　of　the　new　structure　was　established.　The　effect　of　the　interaction　between　the　pile　foundation　and　the　soil　around　the　pile　was　considered，and　the　half　bridge　organic　glass　model　test　was　designed　according　to　the　principle　of　similarity　ratio　to　verify　the　correctness　of　the　simulation　method.　The　verified　numerical　model　was　used　to　establish　the　full　bridge　beam-truss　model　and　the　full　bridge　solid　model　for　the　arch　structure　behind　the　abutment，and　the　effect　of　rise-span　ratio　and　pile　length　on　the　overall　mechanical　performance　was　analyzed.　The　analysis　results　show　that：The　displacement　and　stress　values　of　the　model　test　are　8%　and　21%　different　from　those　of　the　beam-truss　model，and　-3%　and　5.3%　different　from　those　of　the　solid　model.　With　the　increase　of　rise-span　ratio，the　horizontal　constraint　on　the　arch　foot　decreases，the　vertical　displacement　of　the　arch　crown　decreases　relatively，the　axial　force　on　the　main　beam　decreases　gradually，and　the　bending　moment　variation　range　also　decreases　slightly，the　horizontal　force　generated　by　the　temperature　is　more　transmitted　to　the　arch　structure　behind　the　abutment.　With　the　reduction　of　the　pile　length，the　vertical　displacement　of　the　arch　crown　decreases，the　shear　force　at　the　pile　top　decreases　relatively，the　axial　force　on　the　main　beam　decreases　gradually，and　the　range　of　bending　moment　changes　slightly　decreases.　Considering　the　actual　foundation　conditions，the　jointless　bridges　with　shorter　pile　length　and　larger　rise-span　ratio　has　better　overall　mechanical　performance.　©　2024　Editorial　Board　of　Jilin　University.　All　rights　reserved.