Fire　overflow　on　exterior　wall　with　thermal　insulation　system　has　been　studied　by　numerical　simulation.　The　spread　laws　of　fire　overflow　are　analyzed　through　the　temperature　distribution　near　the　window.　The　computational　results　are　compared　with　those　of　test　in　the　Exterior　Insulation　Fire　Barrier　Technical　Guidelines　(EIFBTG).　It　has　been　found　that　the　calculated　maximum　temperature　points　is　closed　to　the　test　on　the　first　floor,　the　first　ceiling,　and　the　points　near　the　above　two　windows.　However,　there　are　differences　between　two　kinds　of　results　above　two　floors　and　ceilings,　and　the　points　near　the　first　window.　It　has　also　shown　that　when　the　HEIR　is　7.5KW,　the　scope　of　damage　of　exterior　thermal　insulation　layer　is　about　15　square　meters　near　the　window.　The　research　would　provide　reference　for　fire　protection　design　of　exterior　wall　thermal　insulation　in　the　high-rise　buildings.