Triterpene saponins are glycosides of cyclic C30 terpenes which consist of triterpenoid sapogenins,sugar,and uronic acid.They are major active ingredients of many medicinal plants,with a range of pharmacological effects.The biosynthesis of triterpene saponins includes the formation of precursors and skeleton of triterpene saponins,as well as the post-modification that regulates the structure diversity.The post-modification of triterpene saponins mainly includes the oxidation/hydroxylation and glycosylation of triterpene skeleton,which are catalyzed by cytochrome P450 monooxygenase and glycosyltransferase,respectively.They are encoded by different supergene family.By means of post-modification,triterpene saponins can form a variety of monomer saponins in the end.Currently,several key post-modification enzymes which are relative to triterpene saponins biosynthesis have been identified and confirmed in a few plants,and a part of candidate genes that most likely involved in the post-modification process have been found.Studies on key post-modification enzymes in triterpenoid saponins biosynthesis were reviewed in this article,which provided a reference for further correlational research and analysis on fine synthesis pathway.