Phthalic　anhydride　was　used　to　corrode　the　aramid　fibers　(AFs)　in　order　to　improve　the　interfacial　compatibility　between　AFs　and　recycled　polyethylene　terephthalate　(R-PET).　Besides,　the　intrinsic　viscosity　and　the　mechanical　properties　of　the　composites　of　AFs/R-PET　could　be　improved　to　realize　the　transformation　from　waste　products　to　engineering　plastics　because　phthalic　anhydride　was　also　the　chain　extender　of　R-PET.　FE-SEM,　XPS,　DSC,　TG　and　MFR　were　used　to　study　the　surface　morphology　and　element　contents　of　AFs　and　the　impact　fracture　morphology,　crystallinity　and　liquidity　of　the　AFs/R-PET　composites.　The　results　show　that　the　surface　roughness　of　AFs　and　the　surface　oxygen　content　are　increased　with　the　increase　of　etching　time.　Compared　with　the　pure　R-PET,　AFs/R-PET　composites　are　easier　to　crystallize　and　the　composites　have　higher　bending　strength　and　impact　strength.　The　maximum　intrinsic　viscosity　of　the　composites　reaches　0.9343dL•g-1　and　the　mechanical　properties　achieve　optimal　values　when　AFs　are　corroded　for　6h.　©　2018,　Journal　of　Materials　Engineering.　All　right　reserved.