In　order　to　have　a　full　recovery　of　the　waste　heat　from　a　vehicle　diesel　engine,　simple　organic　Rankine　cycle　(ORC)　system　and　dual-loop　organic　Rankine　cycle　(ORC)　system　are　compared　and　investigated.　According　to　bench　test　results　of　a　vehicle　six-cylinder　diesel　engine,　the　thermodynamic　models　and　economic　models　of　both　ORC　systems　are　established,　and　the　thermo-economic　comparative　analysis　of　both　ORC　systems　are　done　on　the　basis　of　the　study　on　waste　heat　characteristics　under　engine　various　operating　conditions.　The　results　show　that,　under　engine　entire　operating　conditions,　net　power　output,　augmentation　proportion　of　power　output　and　improvement　of　brake　specific　fuel　consumption　(BSFC)　of　the　dual-loop　ORC　system　are　better　than　the　simple　ORC　system,　the　maximum　value　are　24.38　kW,　8.71%　and　8.01%　separately;　Levelized　Energy　Cost　(LEC)　of　the　dual-loop　ORC　system　is　0.8089　CNY·(kW·h)-1　and　19.26%　lower　than　the　simple　ORC　system.　©　All　Right　Reserved.