In　this　paper,　a　primary　study　on　fatigue　performance　of　strengthening　RC　beams　by　using　prestressed　aramid　fiber　reinforced　polymer　(AFRP)　sheets　with　permanent　anchor　was　carried　out.　Based　upon　the　experimental　study　of　four　specimens,　the　beams　strengthened　with　prestressed　AFRP　sheets　were　compared　with　the　beams　strengthened　with　non-prestressed　AFRP　sheets　on　the　fatigue　failure,　fatigue　life,　mid-span　deflection　and　strain.　And　the　effects　of　different　prestress　levels　of　AFRP　sheets　on　these　behaviors　were　discussed.　The　experimental　results　demonstrated　that,　for　the　comparison　between　the　beams　strengthened　with　prestressed　AFRP　sheets　and　the　beams　strengthened　with　non-prestressed　AFRP　sheets,　the　fatigue　life　was　increased　by　33%　to　74%.　The　fatigue　failure　of　the　RC　beams　strengthened　with　AFRP　sheets　arose　from　the　fatigue　fracture　of　steel　bars.　This　was　because　that　fatigue　performance　of　the　AFRP　sheets　was　better　than　that　of　the　steel　bars.　Finally,　the　formulas　for　computing　the　fatigue　life　of　the　beams　strengthened　with　prestressed　AFRP　sheets　were　proposed.