The　Silicon　carbide　(SiC)　is　the　second　hardest　material　for　single　crystalline　materials,　which　is　only　softer　than　the　diamond,　and　recognized　as　a　super　hard　wide-bandgap　semiconductor　material.　The　cutting　process　of　SiC　is　mainly　done　by　the　abrasives　in　diamond,　which　leads　to　low　cutting　efficiency,　high　loss　of　abrasives,　and　server　cutting　damage.　Thermal　Laser　Separation　(TLS)　uses　the　thermal　effect　of　laser　irradiation　to　cause　the　uneven　expansion　of　materials,　and　cause　the　dynamic　tensile　and　compressive　stress　fields　to　control　the　crack　expansion,　and　realize　the　material　separation.　TLS　consists　two　steps,　firstly　pulsed　laser　or　mechanical　blade　are　adopted　to　form　a　starting　point　for　the　crack;　secondly　continuous　wave　laser　is　moving　along　the　prefabricated　trace　to　separation　the　wafer　by　guiding　the　crack　propagation.　The　separation　process　is　a　controlled　crack　propagation　process　in　brittle　materials　from　the　view　of　fracture　mechanics.　But　there　is　still　not　enough　understanding　of　the　fracture　mechanism　and　parameter　optimization　problem　of　SiC　dicing　with　TLS.In　this　paper,　to　understand　the　separation　process,　we　have　established　a　finite　element　model　with　a　prefabricated　crack　in　ABAQUS.　In　the　simulation　operation,　different　powers　are　set　from　8W　to　15W.　We　obtained　the　temperature　distribution　law　of　SiC　surface　under　different　laser　heat　source　parameters.　The　stress　intensity　factor　of　SiC　prefabricated　cracks　under　the　action　of　laser　heat　sources　was　sorted　out.　The　results　demonstrate　that　the　SiC　fracture　mode　is　type　I　fracture.　By　studying　the　law　of　the　stress　field　distribution　on　the　SiC　surface　and　along　the　depth　direction,　We　further　understand　the　separation　mechanism　of　4H-SiC　dicing　by　continuous　laser.　　©　2022　IEEE.