Cryogenic　wind　tunnel　is　an　equipment　for　the　requirement　of　high　Reynolds　number　test　of　the　aircraft　via　the　method　of　reducing　the　test　temperature.　However,　the　test　validity　is　extremely　possible　to　be　destroyed　by　the　occurrence　of　condensation　in　cryogenic　environment.　To　understand　the　characteristics　of　condensation　flow　over　the　airfoil,　a　two-phase　flow　was　developed　with　the　help　of　ANSYS　Fluent.　For　0.137-m　NACA　0012-64　airfoil,　numerical　simulations　of　32　cases　under　three　different　Reynolds　numbers　(~26　×　106,　~38　×　106　and　~44　×　106)　were　implemented.　The　simulated　results　show　that　only　when　the　temperature　of　local　gas-flow　crosses　the　saturation　line　and　is　lower　than　a　critical　point　there　is　enough　condensate　to　alter　some　flow　properties　noticeably,　such　as　pressure,　temperature　and　Mach　number.　The　achievement　of　maximum　local　supercooled　degree　decreases　with　the　increase　in　operating　total　pressure.　For　a　given　test　Reynolds　number,　when　the　static　pressure　and　temperature　of　the　gas　is　on　the　lower　temperature　side　of　the　saturation　curve,　a　reduction　of　operating　pressure　and　temperature　among　a　reasonable　range　is　also　believed　to　not　cause　the　condensation　effect　on　the　aerodynamic　test.　On　the　bright　side,　lower　operating　pressure　will　provide　the　advantages　of　less　liquid　nitrogen　injection　and　less　drive　power　of　fan.　From　another　point　of　view,　under　the　premise　of　ensuring　that　the　gas-flow　local　temperature　is　higher　than　that　at　Wilson　point,　the　reduction　in　the　operating　temperature　as　much　as　possible　can　greatly　increase　the　test　Reynolds　number.　The　built　two-phase　model　supplies　an　approach　for　investigating　the　condensation　effect　on　airfoil　test　in　cryogenic　wind　tunnel,　and　resulting　findings　guide　the　determination　of　working　conditions　for　airfoil　Reynolds　number　test.　©　2020　Elsevier　Ltd