Epidemic encephalitis B (JE) is a central nervous system infectious disease caused by the neurotropic JE virus. The disease is mainly distributed in the Far East and Southeast Asia of Asia. It is transmitted by mosquitoes and is more common in summer and autumn. Clinically, it develops rapidly with high fever, impaired consciousness, convulsions, tonic spasms and meningeal irritation signs. Severe patients often have sequelae after the disease. The mortality rate and disability rate of JE are very high, and it is one of the main infectious diseases that threaten children's health. Summer and autumn are the peak seasons for the onset of JE, and the distribution of epidemic areas is closely related to the distribution of vector mosquitoes. Some patients have serious sequelae, and the mortality rate of severe patients is relatively high. The pathogen of JE was discovered in Japan in 1934, so it was named Japanese JE. In 1939, my country also isolated the JE virus. After liberation, a lot of investigation and research work was carried out and it was renamed epidemic JE.