In　this　paper,　the　ORC　(Organic　Rankine　cycle)　technology　is　adopted　to　recover　the　exhaust　waste　heat　of　diesel　engine.　The　thermodynamic,　economic　and　optimization　models　of　the　ORC　system　are　established,　respectively.　Firstly,　the　effects　of　four　key　parameters,　including　evaporation　pressure,　superheat　degree,　condensation　temperature　and　exhaust　temperature　at　the　outlet　of　the　evaporator　on　the　thermodynamic　performances　and　economic　indicators　of　the　ORC　system　are　investigated.　Subsequently,　based　on　the　established　optimization　model,　GA　(genetic　algorithm)　is　employed　to　solve　the　Pareto　solution　of　the　thermodynamic　performances　and　economic　indicators　for　maximizing　net　power　output　and　minimizing　total　investment　cost　under　diesel　engine　various　operating　conditions　using　R600,　R600a,　R601a,　R245fa,　R1234yf　and　R1234ze　as　working　fluids.　The　most　suitable　working　fluid　used　in　the　ORC　system　for　diesel　engine　waste　heat　recovery　is　screened　out,　and　then　the　corresponding　optimal　parameter　regions　are　analyzed.　The　results　show　that　thermodynamic　performance　of　the　ORC　system　is　improved　at　the　expense　of　economic　performance.　Among　these　working　fluids,　R245fa　is　considered　as　the　most　suitable　working　fluid　for　the　ORC　waste　heat　application　of　the　diesel　engine　with　comprehensive　consideration　of　thermoeconomic　performances,　environmental　impacts　and　safety　levels.　Under　the　various　operating　conditions　of　the　diesel　engine,　the　optimal　evaporation　pressure　is　in　the　range　of　1.1　MPa-2.1　MPa.　In　addition,　the　optimal　superheat　degree　and　the　exhaust　temperature　at　the　outlet　of　the　evaporator　are　mainly　influenced　by　the　operating　conditions　of　the　diesel　engine.　The　optimal　condensation　temperature　keeps　a　nearly　constant　value　of　298.15　K.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.