The invention discloses a glycosyltransferase mutant and a method for catalytically synthesizing rebaudioside A by using the same. The amino acid sequence of original glycosyltransferase is SEQ ID NO:1. According to the experiment, Asn196, Asn78, Asn400, Asn69, Gln72, Gln198, Gln178, Gln160 and Thr319 are screened on the basis of prediction obtained by starting from surface residues Q, N and T ofUGT76G1 and combining data analysis results of solvent accessible surface area, B-factor and the like, and finally, a UGT-SuSy system of the better mutant strain 76G1_Q72E-N196D-T319E is screened outby virtue of single-point or multi-point iterative mutation in Thr81, so as to realize efficient catalytic synthesis of the rebaudioside A. The glycosyltransferase UGT76G1 or a mutant gene thereof isconnected with a sucrose synthase gene to obtain a recombinant plasmid, and a double-enzyme co-expressed recombinant strain is constructed. By constructing a double-enzyme system, regeneration of in-vivo UDPG is realized, the problem of sources of expensive glycosyl donors is effectively solved, the cost is reduced, and application of biotechnology industry is promoted. The mutant is simple to prepare, the rebaudioside A is synthesized through efficient catalysis in a short time, and the biological enzyme catalysis method is green, environmentally friendly and pollution-free and is more suitable for current green industrial processing and production.