As　a　representative　form　of　public　transportation,　subway　system　is　undertaken　to　satisfy　constantly　increasing　transport　needs　and　developed　commonly　in　many　big　cities.　Among　several　catastrophes　in　subway　stations,　including　fire,　flood,　earthquake,　explosion,　toxic　gas　leakage　etc.,　fire　is　the　most　threatening　hazard　to　passengers.　Subway　fires　had　caused　huge　casualties　and　property　losses　during　the　past　decades.　With　the　development　of　metro　line　network,　more　and　more　transfer　stations　appeared.　Compared　with　the　general　subway　station,　smoke　control　system　of　transfer　station　has　its　particularity　and　complexity.　A　typical　cross-shaped　metro　transfer　station　is　used　as　an　example　for　the　study.　Effect　of　two　different　schemes　of　ventilation　and　smoke　control　in　extreme　conditions　in　which　multiple　fires　happen　simultaneously　on　both　platforms　in　the　transfer　station　are　studied　by　using　numerical　simulation　method.　In　fire　scenario　No.　1,　air　is　supplied　in　underground　one　while　independent　smoke　control　is　taken　in　underground　two　and　three.　In　scenario　No.　2,　based　on　scenario　No.　1,　tunnel　fans　are　used　to　assist　in　smoke　control　by　opening　screen　door.　Fire　source　is　designed　for　t2　rapid　fire　with　peak　2MW.　The　results　show　that,　smoke　spread　in　second　underground　floor　can　be　controlled　effectively　by　both　schemes,　the　measure　used　in　scenario　2　effectively　raises　the　wind　speed　downward　the　stairs　while　lower　temperature　around　stairs,　so　that　stairs　round　fire　source　can　be　used　as　emergency　evacuation　passages　for　a　longer　time,　guaranteeing　a　better　smoke　control　performance　in　interchange　station.　Connecting　the　underground　third　floor　with　tunnel　ventilation　system　by　opening　PSD　can　increase　the　downward　air　flow　velocity　and　decrease　the　air　temperature　at　staircases　near　the　fire.　Period　during　which　the　staircase　near　fire　can　be　used　for　evacuation　is　increased.　Reliable　smoke　control　performance　for　transfer　station　can　be　got.