Objective To introduce a poisoning accident caused by clearing up the disuced bloat pool of green plums. Methods In a certain area in Fujian happened a poisoning accident in which many people poisoned. The site of monitoring was carried out immediately. Results The concentrations of hydrocyanic acid, acetonitrile, methane, and carbon dioxide were very high in the air of the pool. Conclusion The main cause of the poisoning was that the cyanogenic glycosides contained in the nucleolus of the green plums. After broken down, the cyanide was released, and then the cyanide synergistic effect with the asphyxiating gas such as methane and carbon dioxide developed also. Treated the sediment and waste water with bleaching powder and lime, cyanide had been eliminated efficiently.