Paraquat is absorbed through digestive tract, skin and respiratory tract, and its toxicity involves many organs of the whole body. In severe cases, it can lead to MODS, and the lung is the main target organ, which can lead to paraquat lung. Acute lung injury ALI or ARDS in the early stage and alveolar and interstitial fibrosis in the later stage are the main causes of death from paraquat poisoning, and the mortality rate is as high as 50% ~ 70%.