A　systematic　study　on　the　tetramethylsilane-hydorgen　(TMS-H-2)　system　by　high-throughput　thermodynamic　method　is　conducted　with　a　large　experimental　condition　range　(500　2700　K,　0　75　kPa,　and　H-2:TMS　ratio　of　0.1　to　10000)　towards　the　deposition　of　pure　single-crystal　SiC　by　high-temperature　chemical　vapor　deposition　(HTCVD)　method.　The　temperature,　pressure　and　H-2:TMS　ratio　dependence　phase　diagrams　are　calculated　to　describe　the　deposition　condition　of　single-phase　＂gas　+　SiC＂　region.　Due　to　the　etching　effect　of　hydrogen　on　graphite,　the　increasing　temperature　and　pressure　could　suppress　the　formation　of　graphite　and　favor　the　growth　of　SiC　in　the　H-2:TMS　ratio　above　1000,　however,　excessive　H-2:TMS　ratio　could　reduce　the　TMS　consumption　efficiency.　TMS　consumption　efficiency　maps　focusing　on　the　gas　+　SiC　region　based　on　the　phase　diagrams　have　been　carried　out　to　balance　the　deposition　parameters,　SiC　mole　fraction　and　TMS　consumption　efficiency.　When　H-2:TMS　ratio　＞　1000,　an　accepted　window　for　preparing　single-phase　SiC　with　a　high　TMS　consumption　efficiency　(＞90%)　is　provided,　and　this　window　could　expand　furtherly　with　increasing　the　ratio.　TMS　consumption　efficiency　maps　offer　the　theoretic　basis　and　guidance　for　improving　the　quality　and　cost　of　industrial　production　of　single-crystal　SiC　by　HTCVD　method.