Classical isolation methods were used to isolate bacteria strains m irradiated bread.Biochemical characteristics and using of carbohydrate in API identification system were used to determine the two anti-irradiation bacteria.The sensitivity of two anti-irradiation bacteria was studied by infection experiment.Resuhs showed that Bacillus subtilis and Kocuria kristinae were the two anti-irradiation bacteria in irradiated bread.Irradiated dosage is in linear relationship with the number of live bacteria.On account of different concentration,the value of D10 of Bacillus subtilis were 0.758 kGy,0.871kGy,and value of D10 of Kocuria kristinae were 0.720kGy,0.823kGy respectively.