The　fire　smoke　is　one　of　the　most　important　factors　for　the　fire　temperature　field.　Once　the　fire　smoke　has　been　exhausted　effectively,　the　fire　temperature　will　be　reduced　and　the　fire-resistance　performance　of　steel　structures　may　be　improved　as　well.　However,　the　research　on　the　fire　temperature　in　the　space　structures　is　almost　bold,　which　could　lead　to　the　theoretical　analysis　result　on　fire　temperature　is　quite　different　from　the　real　condition.　Accordingly,　the　air　temperature　condition　on　fire　for　large-space　structures　has　been　analyzed.　Taken　into　account　smoke　ventilation,　the　empirical　formula　for　air　temperature　in　large　space　structure　under　fire　has　been　modified.