The　Beijing　Subway　system　carries　about　8　million　passengers　per　day　in　2012,　and　the　congestions　caused　by　large　passenger　volume　has　become　a　major　issue　in　transit　stations　especially　transfer　ones.　In　order　to　suppress　the　congestion　to　an　acceptable　level,　an　indicator　reflecting　transit　station　service　level　is　urgently　needed.　However,　previous　researches　mainly　focus　on　the　passenger　density　of　certain　areas,　such　as　stairs　and　walking　corridors.　This　paper　aims　to　propose　a　composite　indicator　reflecting　the　service　level　of　a　whole　transit　station.　Filed　investigation　of　several　transfer　stations　was　conducted　during　peak　commuting　period,　in　order　to　find　out　the　usual　congestion　points　of　each　passenger　flow　line.　According　to　investigation　results,　Platform　stair,　Exit　AGM　(Automatic　Gate　Machine),　Platform　and　Corridor　entrance　were　chosen　as　key　nodes　to　reflect　transit　station　service　level.　And　the　weight　of　each　key　node　was　decided　by　the　average　passenger　density　ratio,　based　on　simulation　experiment　of　SHD　station.　Finally,　the　service　level　of　SHD　station　was　evaluated　with　fuzzy　comprehensive　evaluation.