Schistosoma japonicum miracidium can survive in water for 2 ~ 3 days. At this time, if snails are encountered, they will take the initiative to invade and develop into mother cells, daughter cells and cercariae in snails (1 cercariae can develop into tens of thousands of cercariae) and then escape; If people and animals move in the water, they will invade the human body through the skin. The damage caused by Schistosoma japonicum to the host is the most serious caused by eggs. Eggs are deposited in the liver and intestinal wall of the host, forming egg granuloma, which eventually leads to hepatosplenomegaly, intestinal wall fibrosis, cirrhosis and ascites. In children, repeated infection can lead to stunting, mental retardation and poor reproductive function, leading to schistosomiasis dwarfism and loss of labor. The principle of prevention and control is to check sick people and cattle every year, kill snails and manage human and animal feces. Feces should be stored for a period of time before use to prevent eggs that can hatch miracidium from falling into snail water, and water source management should be done well. From the founding of New China to 1958, schistosomiasis was basically eliminated in China. But in recent years, there is an upward trend in places with snails and patients. Therefore, the complete eradication of schistosomiasis is an extremely arduous task.