Kevlar　fiber　(KF)　was　modified　by　anionic　grafting　of　nylon　6.　The　nylon6/raw　Kevlar　fiber　composites　(PA6/KFO)　and　nylon6/modified　Kevlar　fiber　composites　(PA6/KF1)　were　prepared　by　extrusion　process.　In　the　mean　time,　DSC　was　used　to　study　the　effect　of　KFO　and　KF1　on　the　nonisothermal　crystalline　behavior　and　melting　characteristics　of　PA6/KF　composites.　Both　KF1　and　KFO　improved　the　Tonsetc　of　PA6,　reduced　its　ttotal,　enhanced　the　relative　intensity　of　the　lower　temperature　melting　peak　of　PA6,　which　attributed　to　their　nucleation.　The　nucleation　effect　of　KF1　is　more　obvious　than　that　of　KFO.　The　Tonsetc　of　all　samples　would　fall　when　the　cooling　rate　accelerated,　at　the　same　time,　a　single　melting　peak　of　PA6　would　be　instead　of　double　melting　peaks.