The　finite　element　analysis　is　applied　to　obtain　the　contact　pressure　of　the　contact　surfaces　at　different　speed.　Based　on　the　three-dimensional　fractal　model　and　Hertz　theory　the　contact　stiffness　of　the　double　locking　toolholder-spindle　system　is　obtained,　then　the　simulation　model　is　built　to　obtain　the　contact　characteristic　of　the　system　at　high　speed.　Based　on　the　theoretical　model　the　influences　of　the　different　parameters　on　the　taper-surface　contact　ratio　and　the　contact　stiffness　are　revealed.　Finally,　the　upper　limit　of　the　speed　and　the　reasonable　ranges　of　the　draw-bar　force,　disk-spring　stiffness　and　pre-tightening　force　are　defined.　All　the　research　results　will　be　a　good　theoretical　basis　for　the　structural　design　and　optimization　of　the　double-locking　toolholder-spindle　system.　©　2017,　Editorial　Department　of　JVMD.　All　right　reserved.