The invention relates to ginsenoside glycosidases which hydrolyzes ginsenosides having higher contents in ginsengs so as to prepare rare ginsenosides with high physioloigical activity. Said ginsenoside glycosidases are derived from microorganism cultures, ginseng plants, almonds, wheat brans, malts and animal livers etc., and are categoried to four types depending on their capability of hydrolyzing the sugar moieties of ginsenosides, namely, ginsenoside glycosidase I, ginsenoside glycosidase II, ginsenoside glycosidase III and ginsenoside-α-rhamnosidase. The invention also relates to the uses of the ginsenoside glycosidases in preparing rare ginsenosides.