ObjectiveTo determine the nature of the food poisoning event that has not gathered the reason. Methods The descriptive epidemiology and case of illness are used to conduct a contrastive study. The bacterium study, the serology examination and the HACCP hygiene investigation method will be adopted as well for investigation and analysis. ResultThe attack rate of poisoning is 6.67%, incubation period 1.5~6.5h, center position incubation period 4.5h and the dangerous ratio of the food roasted chicken legs (OR) is 28.33, which is connected with the poison. The examination result is that the food is infected by the Vibrio parahaemolyticas to mix the Aeromonas sobria. The HACCP investigation determines that the food is poisoned by the overlapping contamination between the utensil and the food, or the dissemination of the disease carried by the staff. ConclusionThis the food poisoning event is caused by the Vibrio parahaemolyticas to mix the Aeromonas sobria.