A　spindle/toolholder　connection　system　is　one　of　the　weakest　sections　in　a　machine　tool.　The　quality　of　machining　is　related　to　its　connection　performance.　Here,　a　model　of　the　spindle/toolholder　system　was　established　based　on　the　contact　finite　element　theory.　Normal　direction　and　tangential　one　actions　between　interfaces　were　considered.　The　taper-to-taper　clearances,　the　taper-to-taper　contact　pressure　and　the　stress　of　the　toolholder　at　different　rotating　speeds　were　analyzed.　It　was　shown　that　under　static　and　low　speed　conditions,　its　connection　performances　are　stable;　however,　when　the　rotating　speed　is　high,　the　tapers　of　the　tool　holder　and　the　spindle　hole　are　departed,　and　their　contact　pressure　is　only　half　of　that　under　the　static　condition,　and　the　stress　of　the　toolholder　grows　significantly　at　the　same　time,　the　connection　performances　get　worse.　Finally,　tests　verified　the　reliability　of　the　analysis.　©,　2015,　Chinese　Vibration　Engineering　Society.　All　right　reserved.