Non-equilibrium　phase　transition　flow　is　prevalent　and　of　great　irreversible　loss　during　the　transonic　mixing　process　of　steam　ejector,　but　its　complex　evolution　law　is　thus　far　unclear.　In　this　study,　a　considerate　two-phase　ejector　model　was　developed　to　investigate　the　non-equilibrium　phase　transition　flow　characteristics　by　means　of　CFD　numerical　simulation,　including　how,　where　and　to　what　extent　the　phase　transition　occurs.　Additionally,　the　quantitative　analysis　of　the　operating　parameters　influences　on　the　phase　transition　flow　and　ejector＇s　entrainment　performance　were　conducted.　Results　showed　that　the　evolution　law　of　condensate　is　highly　consistent　with　the　pressure　fluctuation　of　shock　wave.　Non-equilibrium　condensation　is　to　be　intensified　as　the　primary　fluid　pressure　increases,　and　the　entrainment　performance　thus　worsens.　For　raising　the　secondary　fluid　pressure,　the　case　is　opposite,　the　entrainment　ratio　w　increases　by　17.8　%.　Superheating　the　working　fluids　can　restrain　the　droplet　development,　and　more　small-sized　droplets　therefore　emerge,　but　w　only　raises　by　a　maximum　of　3.53　%.　However,　it　is　hard　to　restrain　the　condensate　generation　in　primary　jet　flow　by　superheating　the　secondary　fluid,　both　suction　pressure　and　w　decrease.　This　study　provides　meaningful　guidance　for　reducing　the　irreversibility　loss　from　non-equilibrium　phase　transition　flow.