Objective:To evaluate the role of beta-2-microglobulin in the development of eqidemic encephalitis B.Methods:Forty-eight cases of epidemic encephalitis B children were divided into medium and severe types and beta-2-microglobulin was measured in their serum and cerebrospinal fluid(CSF) by radio-immunoassay(RIA).Twelve cases of control study was taken simultaneously.Results:At initial period,the serum and CSF concentrations of beta-2-microglobulin in forty-eight cases of epidemic encephalitis B patients were higher than that of the controls( P