The　difficulties　in　numerical　simulation　of　fire　scenarios　in　a　large　subway　transfer　station　are　analyzed.　An　extreme　dangerous　situation　where　fires　happen　in　both　station　and　transfer　hall　in　a　typical　subway　transfer　station,　Dong　Zhimen　transfer　station,　in　Beijing　is　studied.　The　smoke　temperature　and　velocity　fields　in　transfer　channel　and　exits　are　computed.　The　numerical　simulation　is　validated　by　comparison　between　the　results　of　spot　tests　without　hot　smoke　and　those　of　a　comprehensive　numerical　simulation　condition.　It　can　be　found　that　numerical　simulation　is　a　reasonable　method　for　studying　smoke　propagation　in　a　large　subway　transfer　station.　Under　a　multi-point　fire　scenario,　smoke　intervolve　can　happen　in　certain　exits.　This　would　do　harm　to　safety　evacuation　in　subway　station.