Indoor　air　quality　in　a　public　transport　interchange　station　in　rush　hour　has　been　studied.　Carbon　monoxide　is　selected　as　the　main　pollutant　for　description　of　air　quality.　Ventilation　systems,　bus　traffic　and　passenger　flow,　air　quality　have　been　investigated　by　on-site　survey.　Large　eddy　simulation　technology　has　been　used　to　analyze　indoor　air　quality　of　public　transport　interchange　station.　The　boundary　conditions　are　determined　according　to　the　measured　date.　Indoor　air　quality　results　at　heights　of　0.8m　and　1.6m　in　rush　hour　and　two　operating　conditions　of　public　transport　interchange　station　are　calculated.　Results　have　shown　carbon　monoxide　concentrations　at　height　of　0.8m　are　higher　than　those　at　height　of　1.6m.　Air　quality　would　reach　the　harmful　degree　within　5min　to　10min　if　the　ventilation　system　is　not　operating.　The　ventilation　system　should　be　operated　continuously　during　the　peak　hour　in　order　to　meet　the　requirement　of　indoor　air　quality　standards.