To　study　the　influence　of　load　ratio,　fire　exposure　time,　and　composite　parameters　on　the　residual　bending　performance　of　prefabricated　concrete　composite　beams　after　high　temperature,　14　reinforced　concrete　T-shape　composite　beams　were　designed,　where　12　beams　were　subjected　to　fire　tests　and　post-fire　static　test　and　two　beams　were　subject　to　the　static　test　under　room　temperature.　The　interaction　of　precast　concrete　and　cast-in-place　concrete　on　the　composite　surface　was　simulated　by　the　three-dimensional　spring　element　in　ABAQUS,　and　the　calculation　method　of　the　residual　flexural　capacity　of　the　composite　beams　after　the　fire　was　proposed.　The　research　results　show　that　the　residual　capacity　decreases　with　respect　to　the　increasing　fire　time,　the　larger　the　load　ratio,　the　smaller　the　composite　parameters,　and　the　higher　temperature　of　specimens　is　experienced.　The　load　ratio　and　the　composite　parameters　all　have　effects　on　the　residual　capacity　of　specimens.　Taking　120　min　as　an　example,　under　the　same　composite　parameters,　the　residual　capacity　of　the　specimen　with　a　load　ratio　of　0　is　19%　higher　than　that　of　0.　44.　Under　the　same　load　ratio,　the　residual　bearing　capacity　of　the　specimen　with　the　composite　parameter　of　0.　6　is　24%　higher　than　that　of　0.　4.　Considering　that　the　formula　for　calculating　the　residual　bearing　capacity　of　ordinary　reinforced　concrete　beams　after　high　temperature　may　no　longer　apply　to　composite　beams,　a　formula　for　calculating　the　residual　flexural　capacity　of　composite　beams　after　fire　was　proposed　by　introducing　the　reduction　parameters,　and　the　error　between　the　calculated　value　and　the　test　value　is　about　4%　-12%　with　high　accuracy.　©　2023　Science　Press.　All　rights　reserved.