In　this　paper,　the　CFD　numerical　simulation　method　is　used　to　carry　out　the　numerical　simulation　of　the　fire　new　self-designed　deep-sea　mixed-flow　multiphase　pump　under　the　single-phase　pure　water　and　air-water　two-phase　conditions　respectively.　Under　the　single　phase　condition,　the　pressurization　characteristic　and　hydraulic　efficiency　of　the　multiphase　pump　at　three　speeds　of　3000rpm,　3500rpm　and　4000rpm　are　studied　with　the　change　of　liquid　flow　Ql.　Under　the　two-phase　condition,　the　two-phase　pressurization　performance　of　the　multiphase　pump　with　constant　liquid　flowQl　changing　the　inlet　volume　gas　void　fraction　GVF　and　constant　GVF　changing　Ql　is　predicted.　The　range　of　GVF　is　0∼10%,　and　the　range　of　Ql　is　between　5　m3/h　and　90　m3/h.　The　results　show　that　the　mixed-flow　multiphase　pump　has　a　good　pressurization　performance　and　can　maintain　safe,　efficient　and　stable　operation　when　the　GVF　is　less　than　10%　in　the　air-water　two-phase　conditions.　It　is　found　that　the　gas　accumulation　near　the　local　area　of　suction　surface　of　guide　vane　at　the　inlet　of　diffuser　is　the　main　reason　that　the　pressurization　performance　of　the　mixed-flow　multiphase　pump　decreases　slightly　with　the　increase　of　GVF.　©　2021,　Science　Press.　All　right　reserved.