Kevlar　fiber　was　modified　by　anionic　graft　of　nylon　6　oligomer.　Nylon　6/modified　Kevlar　fiber　(PA6/KF1)　composites　were　prepared　by　extrusion　and　injection　process.　XPS,　ESEM　and　FTIR　proved　the　nylon　6　oligomer　was　grafted　onto　the　surface　of　Kevlar　fiber.　DSC　was　used　to　study　the　effect　of　KFO　and　KF1　on　the　isothermal　crystalline　kinetics　and　melting　behavior　of　PA6/KF　composites.　The　results　have　shown　that　the　KF　played　an　role　of　heterogeneous　nucleation　agent　in　the　process　of　crystallization　of　PA6　and　increased　its　crystallization　rate.　The　improved　interfacial　adhesion　between　PA6　and　KF1　in　the　composites　restricted　the　motion　of　PA6　segments,　which　thus　leading　to　the　demotion　of　heterogeneous　nucleation　of　PA6/KF1.　At　low　temperature　(188-192°C),　the　melting　behavior　of　PA6　presented　triplet　peaks　after　isothermal　crystalline,　while　the　melting　behavior　turned　up　double　peaks　at　relatively　high　temperature　(194°C),　The　induction　of　KF　has　influenced　the　melting　behavior　of　PA6　dramatically.