Blocking　the　tunnel　portal　is　one　strategy　in　railway　tunnel　firefighting.　In　order　to　evaluate　the　effect　of　tunnel　portal　sealing　ratio　on　fire　behaviour,　Fire　Dynamics　Simulator　(FDS)　was　used　to　simulate　tilted　tunnel　fire　with　different　slope　angles　varying　from　0%　to　5%,　heat　release　rate　varying　from　10　to　50　MW　and　sealing　ratios　varying　from　0%　to　75%.　Results　show　that　the　experimental　data　of　the　temperature　distribution　inside　the　tilted　tunnel　were　in　good　agreement　with　the　simulation　results.　Moreover,　the　ceiling　temperature　rise　decreases　along　the　tunnel　with　the　increase　of　the　tunnel　portal　sealing　ratio　at　initial　stage　and　then　tends　to　stabilize　because　of　less　oxygen　supply　when　the　heat　release　rate　is　relatively　large.　The　maximum　temperature　rise　decays　exponentially　along　the　tunnel　ceiling　with　distance.　The　current　model　for　temperature　decay　beneath　the　tunnel　ceiling　was　proposed　to　be　modified　by　taking　the　tunnel　entrance　sealing　ratio　into　account.　The　predictions　by　the　modified　model　agree　well　with　the　experimental　measurement.　The　results　could　provide　practical　information　and　knowledge　in　ventilation　system　design　and　emergency　evacuation　for　inclined　railway　tunnels.