Mutagenesis of Bacillus Natto 20646 in corona electric filed was studied for increasing the production of γ-PGA.The infrared spectrum was plotted to make sure that the product was really the γ-PGA.The results show that the death rate of Bacillus Natto 20646 was 97.3%when the bacteria was radiated in the corona field under the voltage of 9kV for 2 min.And there were obvious pucker in the center of ndlz01 colony and there were threadlike things when the inoculated bacteria were pricked by needle after cultivating for 24h.In addition,the bacillus natto which was mutated in corona electric field grew faster and the yield of γ-poly glutamic acid was enhanced obviously;in our experiments the yield of γ-poly glutamic acid by mutated bacteria was 129.78%higher than that of the original bacterium.