The　organic　Rankine　cycle　(ORC)　system　can　effectively　recover　the　waste　heat　energy　of　the　engine,　but　its　performance　is　substantially　affected　by　the　operating　conditions　of　the　engine.　The　road　conditions　control　the　operating　conditions　of　the　engine,　which　determine　the　amount　of　waste　heat　energy　of　the　engine　and　the　performance　of　the　ORC　system.　Therefore,　the　energy　recovery　efficiency　of　the　ORC　system　in　a　vehicle　engine　under　different　road　conditions　must　be　studied.　This　study　establishes　a　vehicle　model　including　engine,　ORC　system,　power　transmission　system,　and　control　system,　and　verifies　the　accuracy　of　the　engine　and　ORC　system.　The　vehicle　model　is　used　to　simulate　and　analyze　the　operating　characteristics　and　energy　recovery　efficiency　of　the　engine　and　ORC　system　under　New　York　City　Cycle　(NYCC)　and　motorway　of　Common　Artemis　Driving　Cycles　(CADC)　road　conditions.　Results　show　that　the　exhaust　energy　is　low　and　fluctuates　frequently　under　NYCC　road　condition,　ranging　from　5.45　kW　to　24.28　kW,　with　an　average　exhaust　energy　of　10.4　kW　and　an　average　energy　recovery　efficiency　of　1.43%.　The　exhaust　energy　is　high　and　fluctuates　slightly　under　motorway　of　CADC　road　condition,　ranging　from　5　kW　to　44.5　kW,　with　an　average　exhaust　energy　of　26.9　kW　and　an　average　energy　recovery　efficiency　of　5.50%.　Therefore,　the　ORC　waste　heat　recovery　system　is　more　suitable　for　motorway　mad　conditions　with　high,　stable　vehicle　velocity,　while　the　urban　mad　conditions　with　low　or　fluctuant　vehicle　velocity　must　be　avoided　as　much　as　possible.