The invention belongs to the field of bioengineering, and specifically relates to a phospholipase A2 mutant and a preparation method thereof. A fallible PCR technology is used for performing random mutation on wild type phospholipase A2 to obtain the phospholipase A2 mutant, and the enzyme activity of the obtained phospholipase A2 mutant is improved by 27% in comparison with the enzyme activity of the wild type phospholipase A2; meanwhile, by use of an enzyme expression system, when the lipase A2 is displayed on the enzyme surface, the yeast cell can be used as a producer of the enzyme, and can serve as a carrier in the immobilized enzyme, the purification and the immobilization and other operations of the enzyme are relieved; the production link is simplified, and the production cost is lowered.