Objective To investigate the reason of Bongkrekic acid food poisoning outbreak， and prevent similar incidents from happening again.Methods Pathogenic factors were determined by rapid detection. Suspicious meal and food were inferred according to the incubation period of pathogenic factors. Poisoning meal and food were determined by combining survey results from epidemiological investigation， food hygienic investigation， environmental hygienic investigation， sampling and detection.Results Epidemiological investigation showed that there was a correlation between food and the morbidity. The incubation period and clinical manifestations of patient were in accordance with the characteristics of Bongkrekic acid food poisoning. Bongkrekic acid was detected in the food sample and patient blood.Conclusion The poisoned meal was the dinner on July 19， 2020， and the poisoned food was stir-fried rice noodles. The main cause of this was the violation of the food safety operation by food factory operator and employees during production and transportation， which caused bacterial proliferation and produced toxin in contaminated rice noodles.