In　the　electrical　discharge　machine　(EDM),　the　slide　carriage　system　of　the　X　axis　connects　the　lathe　bed　and　the　ram　of　the　Y　axis,　its　thermal-deformation　has　a　directly　effect　on　machining　precision.　Based　on　Solid-works　and　ANSYS　Workbench　software　to　build　the　finite　element　model　(FEM)　of　the　slide　carriage　system,　the　heat　generation　of　the　motor　on　the　Y　axis,　and　the　frictional　heat　of　the　bearing　and　guide　as　the　main　thermal　source,　there　are　two　cases:　applied　and　no　contact　thermal　resistance　(TCR)　as　the　thermal-structure　coupling　deformation　analysis.　Established　a　model　of　the　natural　convection　heat　transfer　coefficient　with　the　temperature-change　according　to　the　actual　measured　the　temperature　curve　of　workshop　and　mathematical　logarithm　principle.　The　analysis　told　us　that:　in　the　thermal　analysis　of　precision　mechanical　equipment,　heat　source　comes　from　the　external　environment　temperature　and　motor　heat　production,　at　the　same　time,　the　contact　thermal　resistance　and　the　natural　convection　heat　transfer　coefficient　with　the　temperature-change　for　the　thermal　characteristics　of　the　equipment　will　make　an　important　influence.　©　JVE　INTERNATIONAL　LTD.　VIBROENGINEERING　PROCEDIA.DEC　2016.