A　method　combining　macro　and　micro　was　proposed　to　built　the　contact　stiffness　model　of　spindle-toolholder　joint　at　high　speed.　In　macro　analysis,　the　spindle-toolholder　joint　surface　was　assumed　as　ideal　taper,　the　contact　pressure　distribution　of　taper　surface　was　obtained　by　using　the　finite　element　method.　In　micro　analysis,　the　contact　surface　was　composed　of　many　asperities,　and　based　on　the　contact　pressure　distribution,　the　three-dimensional　fractal　model,　considering　the　influence　of　expand　coefficient,　was　adapted　to　compute　the　contact　stiffness　of　taper　joint.　The　BT40　toolholder　as　the　research　object　was　built,　and　the　consistency　of　the　theoretical　prediction　and　experimenal　results　at　zero　speed　about　the　frequency　response　function　was　good.　Based　on　the　method,　the　relationship　of　the　total　contact　stiffness　and　the　working　speed　or　drawbar　force　was　revealed.　The　limit　speed　was　determined　as　1.5×104　r/min　and　the　reasonable　range　of　drawbar　force　was　obtained　as[8,　12]　kN.　The　research　results　could　be　a　theoretical　basis　for　the　structural　optimization　of　the　spindle-toolholder　and　the　application.　©　2016,　Editorial　Board　of　Journal　of　Huazhong　University　of　Science　and　Technology.　All　right　reserved.