Flank　modification　is　widely　used　in　helical　gear　to　diminish　contact　stress　and　edge　contact,　to　improve　the　transmission　performance.　In　this　paper,　tooth　contact　analysis　is　used　to　simulate　the　modified　helical　gear　driver　with　high-order　parabolic　modification　curve.　The　results　show　that　the　transmission　error　is　diminished,　and　the　meshing　area　is　non-sensitive　to　the　alignment　errors.