In order to develop a novel antibacterial method of food, the influences of the illumination intensity of LED blue light, the mass concentration of citric acid and temperature on the antibacterial property of Escherichia coli O157:H7 in nutrient broth were studied. The results demonstrated that under low temperature (12 ℃), the effect of LED blue light on the antibacterial property of Escherichia coli O157:H7 was better than that under room temperature (25 ℃), and the antibacterial efficiency increased with the increase of illumination intensity. Under low temperature, the influence of citric acid on E. coli O157:H7 was weak, but under room temperature it could obviously slow down its growth rate. Compared with the control group, after exposure to the LED blue light with an illumination intensity of 4 072.3 J/cm², the number of E. coli O157:H7 under the low temperature decreased by (2.60±0.19) lg CFU/mL, while the number only decreases by (0.67±0.12) lg CFU/mLunder the room temperature . After adding citric acid, the antibacterial effect of LED blue light was significantly enhanced. After exposed to the LED blue light with an illumination intensity of 2 471.0 J/cm², the number of E. coli O157:H7 under the low temperature decreased by (5.13±0.11) lg CFU/mL，while it decreased by (3.08±0.11) lg CFU/mL under the room temperature.