Abstract: For the children,viral encephalitis is a common infectious disease of central nervous system,which is characterized by high incidences,unfavourable prognosis and high mortality rate.The Japanese encephalitis virus,herpes simplex virus,enteroviruses,EB virus,cytomegalovirus are the common pathogens.There are some emerging virus also cause encephalitis,such as west nile virus,borna disease virus,banna virus,nipah virus and so on.It is of significance for the doctors and scientific research personnels to study the pathogens of viral encephalitis.