The　spindle　system　heat　problem　is　a　key　problem　that　must　be　considered　for　high　precision　machine　tool.　The　thermal　contact　resistance　(TCR)　affects　the　heat　transfer　performance　of　a　machine　tool,　which　affects　the　machining　accuracy.　In　this　paper,　a　model　considerating　the　bulk　resistance　and　shrink　resistance　surface　of　TCR　was　established　by　using　the　fractal　theory　of　the　contact　surface.　Motor　heat　and　bearing　friction　heat　in　a　vertical　machining　center　motorized　spindle　system　were　analyzed.　In　case　of　considering　TCR　and　without　considering　TCR,　steady　state　temperature　field　and　the　steady　state　thermal　deformation　were　analyzed.　Results　demonstrate　the　importance　of　TCR　to　the　problem　thermal　characteristics　of　motorized　spindle.　The　temperature　will　be　higher　and　the　deformation　will　be　serious　when　TCR　is　considered.　©　2016,　Beijing　University　of　Technology.　All　right　reserved.