The　thermal　efficiency　of　an　engine　is　relatively　low.　Most　of　the　combustion　energy　is　wasted　in　the　atmosphere.　Recently,　the　utilization　of　the　organic　Rankine　cycle(ORC)system　to　recover　the　waste　heat　of　an　engine　has　been　taken　for　improving　the　fuel　economy　of　the　engine　and　reducing　the　consumption　of　fossil　fuel　resources.　Through　the　process　of　the　experiment,　the　characteristics　of　the　exhaust　of　a　diesel　engine　under　multiple　operating　conditions　were　studied　and　a　set　of　organic　Rankine　cycle　waste-heat　recovery　systems　were　designed　in　this　paper.　In　combination　with　the　experimental　results　and　theoretical　calculations,　the　effects　of　four　kinds　of　zeotropic　mixtures　on　the　performance　of　the　organic　Rankine　cycle　waste-heat　recovery　system　under　multiple　operating　conditions,　and　the　impact　of　the　superheat　degree　and　evaporation　pressure　on　the　performance　of　ORC　using　zeotropic　mixtures　are　analyzed;　and　the　variations　of　the　net　power　output,　thermal　efficiency,　exergy　efficiency　of　the　ORC　system　and　the　power　output　increasing　rate　(POIR)　following　the　variations　of　the　engine　behavior　are　discussed.　The　results　show　that　the　net　power　output　of　the　ORC　system　may　reach　as　high　as　24.65　kW.　When　the　superheat　is　10　K　and　the　evaporation　pressure　is　2.0　MPa,　the　power　output　of　the　combined　system　is　increased　by　10.63%.