Aiming at reduce the acetaldehyde concentration in beer,an industrial brewing yeast strain MI 4 was used as original strain and mutagenized with ultraviolet radiation.After primary screening with disulfiram and domestication with media containing acetaldehyde,a mutant strain D-A-14 was obtained with considerably low yield of acetaldehyde.The concentration of acetaldehyde in the beer brewed with the mutant strain was 2.86 mg / L,which was 76% lower than that of MI 4.In the meantime,the beer brewed with the mutant strain contained less higher alcohols and more esters and showed more harmonious flavor.These results demonstrated that the low-acetaldehyde mutant strain D-A-14 would be suitable for beer industry.