Abstract: In order to obtain a lactic acid bacteria with higher GABA yield, a strain of Lactobacillus isolated from the koumiss samples producing more GABA was selected by high performance liquid chromatography, and was designated as strain 43.A phylogenetic tree was created by aliging the 16S rDNA gene sequences of strain 43 and X type strains, and the homology result revealed that the strain 43 was Lactobacillus plantarum. Then, the strain 43 was mutated by ultraviolet radiation.After mutagenesis, one mutant strain designated as strain 43-7 was obtained, whose GABA yield reaching up to 1.051 g/L and 43.6% higher than that of the original strain. Besides, strain 43-7 had strong stability after 10 generation of cultivation. In general, this study provided a new maeteria for the future industrial production of GABA.