This　work　aims　at　studying　and　comparing　the　shear　performance　and　size　effect　of　RC　deep　flexural　members　and　BFRP-RC　(　Basalt　Fiber　Reinforced　Polymer-reinforced　concrete)　deep　flexural　members.　Shear　failure　experiments　were　carried　out　on　4　RC　deep　flexural　members　and　4　BFRP-RC　deep　flexural　members　(　beam　heights　ranging　from　300mm　to　1200mm).　The　development　trends　of　the　load-deflection　curve,　diagonal　crack　width,　concrete　strain,　longitudinal　reinforcement　strain,　and　web　reinforcement　strain　with　the　change　in　structure　size　are　compared　and　analyzed.　The　size　effect　laws　in　the　shear　strength　of　RC　deep　flexural　members　and　BFRP-RC　deep　flexural　members　are　revealed,　and　the　applicability　of　design　codes　and　calculation　methods　is　analyzed.　The　results　show　that;　1)　The　ultimate　load　of　BFRP-RC　deep　flexural　members　is　about　0.　3~0.　5　times　that　of　RC　deep　flexural　members,　and　the　deflection　is　about　1.　4~　1.　7　times　that　of　RC　deep　flexural　members;　2)　When　the　beam　height　increases　from　300　mm　to　1200　mm　(the　horizontal　and　vertical　web　reinforcement　ratio　are　0.　51%)　,　the　nominal　ultimate　shear　strength　of　the　RC　deep　flexural　member　decreases　by　34.　0%　,　while　the　BFRP-RC　deepflexural　member　decreases　by　45.　7%;　3)　For　the　shear　capacity　of　large-sized　members,　the　safety　reserves　of　the　calculation　results　of　design　codes　may　not　be　sufficient　and　the　size　effect　may　not　be　reasonably　considered;　4)　The　theoretical　formula　proposed　by　Jin　et　al.　can　quantitatively　describe　the　influence　of　structural　size　on　the　nominal　ultimate　shear　strength　of　RC　and　BFRP-RC　deep　flexural　members.　©　2024　Chinese　Society　of　Civil　Engineering.　All　rights　reserved.