Fuente: WIPO "tomato" The present invention belongs to the technical field of biological catalytic conversion, and in particular, relates to methods for efficiently preparing rebaudioside M using a biological enzyme method. The method includes: adding rebaudioside A, uridine diphosphate glucose, glycosyltransferase and a salt into a buffer solution, mixing evenly to obtain a mixture, and allowing the mixture to undergo an enzyme-catalyzed reaction in a stirring state to obtain the rebaudioside M. The glycosyltransferase has an amino acid sequence as set forth in at least one of SEQ ID NOS. 1-12. The glycosyltransferase can also be coupled with a sucrose synthase to catalyze the rebaudioside A to produce the rebaudioside M in one step using sucrose as a glycosyl donor.