An　experimental　work　on　the　shear　strengthening　of　reinforced　concrete　(RC)　beams　completely　wrapped　by　large　rupture　strain　(LRS)　FRP　is　presented　in　this　paper.　A　total　of　14　three-point　bending　tests　were　carried　out　on　simply　supported　RC　beams,　with　a　focus　on　the　impacts　of　the　shear　span-to-depth　ratio　(1.53,　2.25,　and　3.01)　and　FRP　reinforcement　ratio　(0.37　%,　0.75　%,　and　1.12　%)　on　the　shear　behavior　of　RC　beams　strengthened　with　LRS　FRP.　For　the　beams　with　a　median　length,　the　ductility　coefficients　increased　by　81　%,　154　%,　and　335　%　with　the　increase　in　FRP　reinforcement　ratio.　For　the　long　beams,　the　ductility　coefficients　increased　by　116　%,　286　%,　and　470　%　as　the　FRP　reinforcement　ratio　improved.　The　ductility　markedly　improved　with　the　increase　in　shear　span-to-depth　ratio.　PET　FRP＇s　fracture　was　not　found　at　the　ultimate　state,　and　the　improvement　in　midspan　deflection　after　the　peak　state　was　mainly　contributed　by　the　shear　deformation.　The　strengthened　specimens　exhibited　a　ductile　shear　failure　mode.　For　the　short　RC　beams,　the　shear　capacity　was　slightly　enhanced,　and　the　ductility　was　not　improved　after　being　strengthened.　The　strengthened　short　RC　beams　still　showed　a　brittle　diagonal　compression　failure　mode.　The　experimental　shear　contribution　of　PETT　FRP　was　compared　with　the　prediction　of　the　existing　design　guidelines.　Finally,　an　effective　strain　model　of　PET　FRP,　including　the　shear　span-to-depth　ratio　effect,　was　proposed　and　verified　with　the　experimental　results.