Temperature　distribution　and　heat　partition　have　a　significant　impact　on　tool　life　and　machined　surface　integrity　in　metal　cutting　process.　In　this　work,　the　concept　of　non-uniform　heat　partition　of　the　shear　heat　source　on　the　shear　plane　was　proposed,　and　an　improved　cutting　thermal　model　was　proposed　based　on　this　concept.　The　improved　thermal　model　had　a　continuous　temperature　field　at　the　shear　plane　compared　with　the　previous　thermal　model.　Comparing　the　thermal　model　before　and　after　improvement　with　the　finite　element　model　(FEM),　it　was　found　that　the　temperature　distribution　of　the　improved　thermal　model　was　closer　to　the　FEM.　In　addition,　a　calculation　method　for　the　heat　partition　coefficient　of　the　shear　heat　source　considering　mass　transfer　and　the　ratio　of　the　heat　flow　entering　workpiece,　chip　and　tool　to　the　total　heat　generated　during　the　cutting　process　were　proposed　based　on　the　improved　thermal　model.　The　results　were　compared　with　the　regression　models　proposed　before,　and　showed　that　the　shear　angle　is　an　indispensable　factor　for　analyzing　the　heat　flow　in　the　cutting　process　when　the　thermophysical　properties　of　workpiece　remain　unchanged.