In　order　to　study　the　flow　behavior　and　optimize　separation　performance,　a　three-dimensional　numerical　model　of　an　improved　supersonic　separator　was　developed.　The　proposed　model　takes　into　account　the　compressible　and　strong　swirling　effect.　Four　widely-used　turbulence　models　include　Sparlart-Allmaras　model,　realizable　k-epsilon　model,　shear-stress　transport　(SST)　k-　model,　and　Reynolds　stress　model　(RSM)　were　validated　and　compared　by　the　experimental　date　reported　in　the　literature.　The　comparison　results　indicated　that　RSMs　have　great　potential　to　predict　the　flow　inside　supersonic　separator.　Based　on　the　established　numerical　model,　the　distribution　of　critical　parameters　such　as　temperature,　pressure,　and　Mach　number　was　obtained.　The　influence　of　the　pressure　loss　ratio　on　the　shockwave　location　occurred　at　the　divergence　section　of　the　Laval　nozzle　was　systematically　studied.　Analysis　about　the　relationship　between　the　pressure　effect　and　shock　wave　location　was　carried　out　to　explore　the　principal　factors　that　limit　the　performance　of　the　supersonic　separator.