A　thermo-mechanical　coupling　model　for　a　flat　plane　and　an　elasto-plastic　rough　surface　based　on　3D　fractal　theory　was　established.　The　model　considered　the　interaction　between　asperities,　and　integrated　the　heat　flux　coupling　between　the　sliding　surfaces.　To　obtain　the　distribution　of　the　VonMises　equivalent　stress　under　the　different　solid　body　contact　deformation　property　during　the　sliding　process,　the　thermo-mechanical　problem　under　this　3D　model　was　solved　by　the　finite　element　method.　The　numerical　results　from　the　analysis　and　simulation　showed　that　the　distribution　of　VonMises　equivalent　stress　was　very　uneven.　The　VonMises　equivalent　stress　located　in　the　middle　of　the　local　contact　region　was　large.　The　VonMises　equivalent　stress　on　local　contact　region　increased　while　the　relative　sliding　happened,　and　it　becam　larger　with　the　deformation　of　the　plane　pair　decreasing.　But　when　the　＂hot　spotting＂　on　the　frictional　interface　came　into　being,　the　VonMises　equivalent　stress　decreased　because　of　the　local　thermal　expansion.