The　effect　of　slope　on　smoke　propagation　in　an　urban　traffic　tunnel　fire　scenario　under　natural　ventilation　is　studied　by　large　eddy　simulation.　For　a　tunnel　of　range　from　no　5　degrees　slope,　the　transverse　and　lognitudinal　temperature　distributions　of　smoke　layer,　the　highest　temperature　on　tunnel　ceiling　are　computed.　These　numerical　results　are　compared　with　those　of　tunnel　with　corresponding　horizontal　tunnel.　It　has　been　found　that　the　slope　has　a　great　effect　on　smoke　temperature　along　longitudinal　direction.　Especially　in　the　ascending　part　downstream　of　fire　source,　smoke　layer　descends　quickly.　The　highest　temperature　position　on　tunnel　departures　from　the　upper　point　of　fire　source　on　downhill　side.　But　the　highest　temperature　of　5%　slope　does　not　vary　greatly　by　comparison　of　that　in　tunnel　of　zero　slope.　These　results　can　provide　reference　on　fire　protection　design　of　urban　traffic　tunnel.