This　paper　presents　the　parametric　optimization　and　performance　analysis　of　ORC　(organic　Rankine　cycle)　system　using　GA　(genetic　algorithm)　for　recovering　exhaust　waste　heat　of　a　diesel　engine.　First,　the　effects　of　three　key　parameters,　including　evaporation　pressure,　superheat　degree　and　condensation　temperature　on　the　system　performances　are　conducted　with　POPA　(net　power　output　per　unit　heat　transfer　area)　and　EDR　(exergy　destruction　rate)　as　objective　functions.　The　optimal　evaporation　pressure,　superheat　degree　and　condensation　temperature　corresponding　to　the　maximum　POPA　and　the　minimum　EDR　are　provided　under　engine　various　operating　conditions.　Subsequently,　as　a　key　component　of　the　ORC　system,　the　performance　of　a　fin-and-tube　evaporator　used　in　this　ORC　system　is　evaluated.　The　results　show　that　the　optimal　evaporation　pressures　are　mainly　influenced　by　the　engine　operating　conditions,　whereas　the　superheat　degree　and　the　condensation　temperature　present　a　slight　variation　over　the　whole　operating　range.　Furthermore,　the　PPTD　(pinch　point　temperature　difference)　in　the　evaporator　may　occur　at　different　positions　with　the　variation　of　engine　operating　conditions.　At　engine　maximum　rated　power　point,　the　ORC　system　can　achieve　maximum　POPA　of　0.74　kW/m(2),　and　the　ratio　of　maximum　effective　heat　transfer　area　to　actual　area　of　the　evaporator　is　69.19%.　(C)　2015　Elsevier　Ltd.　All　rights　reserved.