Abstract: Taking high fermentability as the screening basis,the yeast strain with good production performance was screened by air plasma mutagenesis. The results showed that the optimal time for mutagenesis of bread yeast BY-3 by air plasma was 10 s. Strain 3G-28 with high fermenting power was screened by mutagenesis. Compared with the original strain BY-3,the fermenting capacity of strain 3G-28 increased by 48.57%,the sucrase activity was 71.89% lower,and the ability to resist glucose repression was 34.84% higher. It had better passage stability and low temperature adaptability:The fermenting capacity could still maintain 87.50% after 15 passage times. After storage at-20 ℃ for two weeks,the relative fermenting power of the strain reached 76.10%,and that of the yeast paste was 83.91%. The results showed that the air plasma technology could effectively mutate baker’s yeast BY-3,which provided a certain basis for the improvement and breeding of baker’s yeast.