The　flexural　performance　of　reinforced　concrete　beams　(RC)　strengthened　by　prestressed　aramid　fiber　reinforced　plastic　(AFRP)　sheets　with　permanent　anchor　have　been　tested　and　shown　in　companion　paper　(Deng　&　Xiao　2010).　Based　on　sectional　analysis,　the　formulas　for　calculating　the　bearing　capacity　of　beams　strengthened　with　prestressed　AFRP　sheets　were　established　in　this　paper.　By　these　formulas,　the　theoretic　results　of　cracking,　yield　and　ultimate　moments　and　its　corresponding　deflections　at　these　points　were　derived　and　compared　with　the　experimental　test　results　of　beams.　The　comparison　analysis　show　that,　the　analytical　results　of　tested　RC　beams　are　in　coincidence　with　the　experimental　results.　©　2011　Tsinghua　University　Press,　Beijing　and　Springer-Verlag　Berlin　Heidelberg.