Non-covalently　functionalized　carbon　nanotubes　are　more　attractive　for　multifunction　composites　because　they　preserve　nearly　all　the　nanotubes＇　intrinsic　properties　and　enhance　the　electroconductivity　of　polymer　composites.　However,　It　is　seldom　reported　that　they　make　dramatic　improvement　in　mechanical　properties.　In　this　paper　we　have　successfully　prepared　a　poly(vinyl　alcohol)　(PVA)　nanocomposite　with　a　non-covalently　functionalized　carbon　nanotube　(DOC-MWNTs)　using　a　simple　method,　which　achieve　a　significant　enhancement　in　mechanical　properties.　The　tensile　modulus　and　tensile　yield　strength　of　the　PVA　composite　film　containing　5　wt%　DOC-MWNTs　increased　by　140%　and　65%,　respectively,　comparing　to　the　pure　PVA　film.　FT-IR,　TEM,　SEM,　and　DSC　were　used　to　investigate　the　MWNTs　and　PVA/MWNTs　nanocomposites.　The　results　show　that　the　separately　dispersed　DOC-MWNTs　filler　throughout　the　PVA　matrix　and　the　strong　adhesion　between　the　DOC-MWNTs　filler　and　the　PVA　matrix　are　responsible　for　the　significant　reinforcement　of　the　mechanical　properties　of　the　composite　prepared.　©　2007　Elsevier　Ltd.　All　rights　reserved.