Abstract: Microwave is a high-frequency electromagnetic waves. People gradually recognized it as a significant physical mutagen.A high-ethanol-yield Saccharomyces cerevisiae strain Y-9-3 was acquired by UV irradiation and microwave mutation fromSaccharomyces cerevisiae 31206 in this paper. The mutant strain has a higher alcohol-production ability, which could achieve18.0 %,and it also has a good stability of producing ethanol.