According　to　the　heat　collection　characteristics　of　parabolic　trough　solar　collector，R600　and　R245fa　are　selected　as　circulating　working　fluids.　The　thermo-economic　models　of　basic　organic　Rankine　cycle（BORC）and　the　ORC　system　with　internal　heat　exchanger（IHE-ORC）are　established　with　the　exergy　efficiency　and　levelized　energy　cost（LEC）as　objectives，respectively.　Bi-objective　optimization　is　conducted　using　the　non-dominated　sorting　genetic　algorithm.　The　optimal　thermo-economic　performance　of　two　systems　with　two　working　fluids　are　obtained　using　TOPSIS　with　entropy　weight　method　integrated.　The　variations　of　thermo-economic　performance　of　the　systems　with　evaporation　pressure，superheat　degree　and　condensation　temperature　are　analyzed.　The　results　show　that，under　optimization　and　decision　making，when　R245fa　is　used，IHE-ORC　system　has　clear　advantage　in　thermodynamic　performance　with　the　optimal　exergy　efficiency　and　LEC　of　54.11%　and　0.1548　$/kWh，respectively.　When　R600　is　used，BORC　system　exhibits　better　economic　performance　with　the　optimal　exergy　efficiency　and　LEC　of　49.89%　and　0.1318　$/kWh，respectively.　Within　the　variation　range　of　operating　parameters，the　exergy　efficiency　and　LEC　of　IHE-ORC　system　are　always　higher　than　those　of　BORC，and　much　higher　exergy　efficiency　is　obtained　when　using　R245fa，while　much　lower　LEC　is　achieved　when　using　R600.　©　2024　Science　Press.　All　rights　reserved.