In　this　paper,　a　thermoeconomic　model　of　a　dual　loop　organic　Rankine　cycle　(ORC)　system　has　been　developed　to　analyze　both　the　thermodynamic　and　economic　performance　of　several　working　fluid　groups　for　the　purpose　of　compressed　natural　gas　(CNG)　engine　waste　heat　recovery.　The　effects　of　six　key　parameters　on　the　thermoeconomic　indicators　of　the　dual　loop　ORC　system　are　investigated.　Furthermore,　a　multi-objective　genetic　algorithm　(GA)　is　employed　to　solve　the　Pareto　optimal　solutions　from　the　viewpoints　of　maximizing　net　power　output　and　minimizing　total　investment　post　over　the　whole　operating　range　of　the　CNG　engine.　The　most　suitable　working　fluid　group　is　screened　out,　then　the　optimal　parameter　regions　are　determined.　The　results　show　that　a　higher　evaporation　pressure　and　a　lower　condensation　temperature　exhibit　a　positive　effect　on　the　thermoeconomic　performances　of　the　dual　loop　ORC　system　while　the　effects　of　variation　in　superheat　degree　and　exhaust　outlet　temperature　on　the　thermoeconomic　performances　are　not　obvious.　The　optimal　evaporation　pressure　of　the　high　temperature　loop　ORC　(HT　cycle)　is　always　above　2.5　MPa.　The　optimal　condensation　temperature　of　the　HT　cycle,　optimal　evaporation　temperature　and　condensation　temperature　of　the　low　temperature　loop　ORC　(LT　cycle)　are　all　kept　almost　constants.　In　addition,　the　optimal　exhaust　outlet　temperature　is　mainly　influenced　by　the　engine　speed.　At　the　rated　condition,　the　dual　loop　ORC　system　has　the　maximum　net　power　output　of　23.62　kW　and　the　minimum　electricity　production　cost　(EPC)　of　0.41　$/kW　h.　The　thermal　efficiency　of　the　dual　loop　ORC　system　is　in　the　range　of　8.97-10.19%　over　the　whole　operating　range.