The regiospecific glycosylation of pentacyclic triterpenoids by UGT73F17, a new glycosyltransferase from Glycyrrhiza uralensis, is highlighted. UGT73F17 exhibited strict substrate specificity toward the carboxyl group at C-30/C-29 of pentacyclic triterpenoids, and showed high promiscuity to sugar donors. UGT73F17 represents the first identified triterpenoid 30/29-O-glycosyltransferase, and could be used as an effective biocatalyst to synthesize glycosyl ester saponins.