Abstract: Objective To explore the relationship between the enteroviruses infection and the epidemic of aseptic.Methods The outbreak cases of aseptic encephalit is from Cangshan county in 1994 and Qixia city in 1996,and the cases of aseptic encephalitis admitted to the two hospitals of Jinan city from July of 1996 to March of 1997 were investigated on epidemiological and clinical character istics.Some stool or cerebrospinal fluid(CSF)specimens from cases were collected and used for the enter oviruses isolation or/and polymease chain reaction(PCR)detect ion.Results The epidemic peak seasons of aseptic en-cephalitis were spring/summer or summer/autumn.Most cases were infants,young children and primary school children.The clinical symptoms of aseptic encephalitis were common with fever and central ner vous systemic signs but few with diarrhea and rash.Most cases recovered within 10 to 19 days of disease course,but a few cases died.The two outbreak cases were primarily diagnosed as viral encephalitis caused by cox ackievirus(Cox)group B infect ion because the dominant enterovirus isolates from stool specimens were CoxB3 and CoxB5,respectively.Eight cases from the two hospitals of Jinan city were positive to CoxB PCR detection,among them 3 CoxB3 virus strains were isolated,and confirmed as viral encephalitis caused by CoxB virus infection.Conclusion The etiology of the virial encephalitis epidemics in some areas of Shandong province was mainly caused by CoxB viruses infection.The surveillance and studies on prevention of the enterovial encephalitis should be carried out in the future.