Provided are the use of glycosyltransferases gGT25, gGT13, gGT30, gGT25-1, gGT25-3, gGT25-5, gGT29, gGT29-3, gGT29-4, gGT29-5, gGT29-6, gGT29-7, 3GT1, 3GT2, 3GT3, 3GT4 and derived polypeptides therefrom in the catalyzed glycosylation of terpenoid compounds and the synthesis of new saponins, wherein the glycosyltransferases can specifically and efficiently catalyze tetracyclic triterpenoid compound substrates at positions C-20 and/or C-6 and/or C-3 during hydroxyl glycosylation, and/or transfer the glycosyl from a glycosyl donor to the first glycosyl of the tetracyclic triterpenoid compounds at position C-3, so as to extend the sugar chain. The glycosyltransferases can also be used for constructing man-made synthetic rare ginsenosides and a variety of new ginsenosides and derivatives thereof.
