Objective To investigate a case caused by mushroom poisoning and identify the mushroom in Qianshan, Jiangxi Province. Methods The case was studied with the epidemiological investigation, clinical treatment data, and the suspicious mushroom samples were identified by morphology and molecular biology. Results The epidemiological investigation showed that all the patients ate mushrooms picked by themselves, the incubation period was about 4 hours, and the typical symptoms included gastroenteritis, vomiting and so on. After treatment with fluid support, corticosteroid, liver protection, all patients recovered after 3 days. The molecular biological evidence showed that the samples were probably Chlorophyllum molybdites. Conclusion The case was caused by Chlorophyllum molybdites poisonous mushroom. The poisonous mushroom species could be identified combined with epidemiology, morphology and molecular biology method.