The　prediction　of　thermo-mechanical　behavior　for　machine　tools　is　important　during　the　designing　period.　The　performance　of　high-speed　machine　tools　depends　not　only　on　their　stiffness　but　also　on　their　thermal　behaviors.　Especially,　the　mechanical　and　thermal　characteristics　of　joints　affect　the　behaviors　of　machine　tools　notably.　The　purpose　of　this　paper　is　to　establish　a　thermo-mechanical　model　for　machine　tools,　by　using　finite　element　analysis　(FEA)　method　to　study　temperature　expansion　and　thermal　deformation.　Unlike　the　methods　developed　by　other　researchers　that　mainly　focused　on　specific　kind　of　joints,　the　proposed　model　studied　various　joints　on　machine　tools.　To　improve　the　accuracy　of　calculation,　this　model　took　both　the　thermal　contact　resistance　(TCR)　and　contact　stiffness　of　the　joints　into　account,　and　the　coupling　between　the　TCR　and　contact　stiffness　was　also　studied　here.　Based　on　the　Hertz　theory,　fractal　geometry　was　used　to　analyze　the　TCR　and　contact　stiffness　on　the　joints.　Experiments　were　set　up　to　test　the　transient　temperature　change　and　the　thermal　deformation　characteristics　of　a　vertical　machine　center　(VMC).　The　results　showed　that　the　proposed　model　can　accurately　simulate　thermal　characteristics　of　machine　tools.