Organic　Rankine　cycle　(ORC)　can　effectively　recover　the　waste　heat,　and　enhance　the　total　thermal　efficiency,　and　deviate　the　impact　to　the　environment　while　the　engine　is　operating.　In　this　paper,　a　regenerative　organic　Rankine　cycle　was　studied　for　the　waste　heat　recovery　application　from　the　engine　exhaust　gas.　The　mathematical　model　of　the　ORC　was　built　up　in　Matlab　and　the　working　parameters　were　optimized　using　genetic　algorithm　(GA).　The　results　indicate　the　optimized　thermal　efficiency　can　achieve　22%.　The　waste　heat　of　the　engine　exhaust　gas　could　be　fully　harnessed　by　the　regenerative　ORC.