Abstract: Objective The epidemioligical char acteristics of viral encephalit is and proportion of Japanese B Encephalitis (JE)in viral encephalitis in Shanxi province were known by analyzing surveillance data for viral encephalitis in Ankang,Baoji and Weinan cities.Methods Elisa method for JE IgM test was used;data were reported level by level and analyzed by Epidata and Excel softwares.Results In 398 cases,cases with positive JE IgM occupied 19.10%(76 cases).Rates of positive blood specimens collected within 7 days,after 7 days after onset and rate of positive cerebr ospinal fluid(CSF)were respectively 26.24%,18.18% and 20.59%.There was no statistic significance during positive rates.Concordance rates of results between blood specimens collected within 7 days and after 7 days after onset and CSF were respectively 86.67% and 80.00%.Tendency of onset for viral encephalitis and JE were similar dur ing June to September,but viral encephalitis slightly peaked in November.Cases aged less than 15 years old in viral encephalitis cases occupied 73.62%;JE IgM positive cases aged less than 5 years old were the highest,36.84%;5~10 age group in the other viral encephalitis cases occupied hig hest,40.68%.Dispersive children and peasants in JE IgM poitive cases occupied higher,71.05%,students in the other viral encephalitis cases occupied higher,56.83%.JE IgM positive cases with no vaccination history and with unknown vaccination history occupied 76.31%.67.11% of JE IgM positive cases were cured and case fatality ratio was 9.21%,83.23% of the other virual encephalitis cases were cured and case fatality ration was 31.1%.Conclusion Blood collection within 7 days and after 7 days after onset for JE IgM test is significant for JE diagosis.Strengtheninglab and epidemiologic surveillance for viral encephalitis will provide important basis for JE/viral encephalitis control.While JE vaccination rate is improved and JE prevention and control in children is done better,JE prevention and control in adult especially peasants should be strengthened.