The　competitive　growth　process　of　the　4H　and　6H　polytypes　of　SiC　is　studied　by　a　competitive　Kinetic　Monte　Carlo　model(KMC),　which　takes　the　atoms　of　silicon　and　carbon　as　the　elementary　kinetic　particle　to　fully　account　for　the　interaction　energy　between　atoms.　In　the　competitive　KMC　model,　the　crystal　lattices　of　two　polytypes　are　represented　by　a　structured　mesh　which　fixed　the　site　positions　at　the　perfect　crystal　lattice　positions.　Kinetic　events　with　competitive　growth,　such　as　deposition,　diffusion　are　considered　in　physical　criterion　in　the　model.　Moreover,　the　model　not　only　considers　the　interaction　energy　between　the　same　kind　of　atoms　(Si-Si),　but　also　considers　the　interaction　energy　between　different　types　of　atoms　(Si-C).　Based　on　the　KMC　model,　the　effects　of　growth　conditions　on　the　competitive　growth　of　4H-　and　6H-　SiC　were　studied.　The　competitive　KMC　simulation　results　show　that　the　higher　temperature　and　the　larger　proportion　of　Si　source　in　the　mixture　will　promote　the　preferential　growth　of　6H　polytype　during　competitive　growth.　Meanwhile,　with　the　increase　of　temperature　and　Si/C　ratio,　the　phenomenon　of　atom　aggregation　growth　on　crystal　surface　becomes　more　and　more　obvious.　©　2021　Elsevier　B.V.