Based　on　prospect　theory,　travelers＇　route　choice　behavior　under　traffic　incident　is　studied.　First,　utility　function　of　travelers＇　route　choice　is　proposed　applying　prospect　theory,　and　total　travel　time　is　taken　as　utility,　considering　probability　of　traffic　incident.　Then,　after　analysis　the　distribution　regularity　of　utility　function,　travelers＇　perception　utility　is　modeled　considering　the　utility　obeying　continuous　random　distribution.　Through　discrete　series　for　continuous　function,　route　choice　model　is　built.　A　case　study　is　conducted　to　describe　the　route　choice　behavior,　and　the　influence　of　characteristic　of　traffic　incident　to　utility　and　choice　result　are　analyzed,　which　illustrates　that　the　reference　point　when　perception　utility　equals　to　zero　is　not　the　expectation　of　actual　utility　distribution,　less　than　the　expectation.　Copyright　©2015　by　Science　Press.