Velocity　fields　on　the　platform　area　and　flow　rate　of　the　smoke　extraction　system　were　experimentally　measured　under　the　different　fan-operation　modes　in　an　actual　subway　station　in　Beijing.　The　velocity　at　the　four　tunnels　connected　with　the　station　and　velocity　at　the　stairs　between　platform　and　concourses　were　obtained.　Through　simulation　based　on　the　measured　results,　the　smoke　velocity,　temperature　and　concentration　in　case　of　station　fire　under　the　different　fan-operation　modes　were　analysed,　and　the　optimal　smoke　extraction　mode　was　proposed.　Improved　advices　about　the　issues　of　the　current　extraction　mode　were　put　forward,　to　offer　reference　for　the　current　running　modes　of　the　subway　extraction　system　and　the　design　of　the　future　subway　extraction　system.