In　this　study,　poly　(vinyl　alcohol)　(PVA)　composites　reinforced　by　multiwall　carbon　nanotubes　(MWCNTs)　functionalized　with　either　phenolic　hydroxyl　groups　(MWCNTs-f-OH)　or　PVP　molecule　(PVP@MWCNTs)　were　fabricated.　The　objective　was　to　elucidate　the　effect　of　different　MWCNTs　surface　functionalization　on　the　mechanical　properties　of　the　nanocomposites.　It　was　found　that　both　of　PVP@MWCNTs　and　MWCNTs-f-OH　had　a　good　dispersion　in　PVA　matrix.　However,　the　MWCNTs-f-OH　had　stronger　effective　interfacial　interaction　with　PVA　matrix　than　PVP@MWCNTs,　owe　to　the　formation　of　hydrogen　bonds　between　MWCNTs-f-OH　and　PVA.　The　stress-strain　measurements　showed　that　the　Young＇s　modulus　and　tensile　strength　of　MWCNTs-f-OH/PVA　with　only　1.0　wt.%　contents　increased　by　200　and　100%　compare　with　that　of　PVA,　respectively.　The　findings　of　this　experimental　study　emphasized　the　critical　role　of　MWCNTs　surface　morphology　in　determining　the　mechanical　properties　of　nanocomposites,　and　shed　new　light　on　understanding　and　advancing　the　properties　of　carbon　nanotube　based　composites.