In　practical　engineering,　the　size　of　the　component　which　need　shear　strengthening　is　often　much　larger　than　that　of　the　test　specimen.　Therefore,　the　analytical　models　and　design　equations　established　from　these　studies　may　not　predict　the　actual　behavior　of　large-scale　beams　strengthened　with　CFRP.　A　series　of　geometrically　similar　CFRP　U-wrapped　strengthening　concrete　beams　were　designed　and　tested,　with　the　maximum　beam　height　reaching　1200　mm.　In　addition,　the　effect　of　CFRP　ratio　on　the　size　effect　of　shear　performance　of　CFRPstrengthened　beams　is　studied.　All　beams　were　subjected　to　a　complete　process　to　measure　CFRP　strain.　In　the　test,　shear　failure　occurred　in　all　beams,　accompanied　by　CFRP　debonding.　External　CFRP　could　significantly　improve　the　shear　capacity　of　beams.　While　the　reinforced　beam　still　exists　obvious　size　effect.　Even　when　the　CFRP　ratio　is　0.2505%,　the　strength　of　the　strengthened　beam　still　decreases　by　35%.　Moreover,　based　on　the　test　results,　the　accuracy　and　safety　of　the　calculation　formula　of　shear　capacity　in　relevant　design　codes　are　discussed.　Furthermore,　a　comparison　between　experimental　data　and　theoretical　data　by　the　size　effect　law　(SEL)　was　made.　The　good　consistency　indicates　the　rationality.