In　this　study,　three　full-scale　experiments　and　a　series　of　numerical　simulations　were　conducted　to　investigate　the　influence　of　subway　platform　height　and　atrium　ceiling　height　of　subway　stations　on　smoke　control　by　mechanical　exhausting　systems.　The　smoke　temperature　variation　with　time,　maximum　temperature　distribution,　and　smoke　stratification　were　discussed.　Results　showed　that　the　atrium　had　capacity　to　store　smoke,　especially　at　the　early　stage　of　smoke　spread.　However,　the　efficiency　of　smoke　extraction　did　not　increase　simply　with　the　rise　in　platform　height　and　atrium　ceiling　height,　and　favorable　smoke　exhaust　velocity　was　crucial　for　smoke　elimination.　The　optimal　smoke　exhaust　velocity　was　studied　by　numerical　simulation　and　it　was　found　that　the　area　of　smoke　diffusion　in　subway　stations　with　a　higher　platform　was　significantly　smaller　under　the　optimal　smoke　exhaust　velocity.　In　addition,　a　prediction　model　of　optimal　smoke　exhaust　velocity　with　subway　platform　height　was　proposed.　This　study　could　provide　on-site　data　and　smoke　spread　characteristics　for　smoke　control　design,　operation,　and,　significantly,　guide　safety　evacuation　of　the　exhaust　system　of　subway　stations.