Abstract: In order to make the pathogenic bacteria inactivation of irradiation better on food processing, Listeria, Salmonella and e. coli O157∶H7 were inoculated into tomato, fresh-cut carrot, packaged tofu, nutrient broth, blanched almonds, blanched peanut and celery mixture, blanched mustard green and soybean, dried apricots, chilled pork and frozen pork respectively, and the influence factors, such as irradiation dose, medium temperature, type of strain, medium type and packaging type, on pathogenic bacteria inactivation were studied. The results show that different mediators and pathogenic bacteria species have great influence on pathogenic bacteria inactivation. The e. coli O157∶H7 is the most sensitive (a higher sensitivity means a stronger pathogenic bacteria inactivation), and Salmonella is more sensitive than Listeria in most mediators. As for the same kind of pathogenic bacteria species, water content and component of mediator are significant factors for pathogenic bacteria inactivation. Higher water content can enhance pathogenic bacteria inactivation, pathogenic bacteria in pork is harder to be killed than that in vegetables. The resistance of pathogenic bacteria in freezing medium to irradiation increases, and the sensitivity of pathogenic bacteria relatively increases in the presence of oxygen.