Abstract: An Analysis on the data of epidemic cerebrospinal meningitis from 1971 to 1995 in Zibo by using circle distribution was carried out. The results showed that there were significant season peaks of the morbidity and death rate of this disease.The peak period of morbidity was from Feb.22 to May 23 and peak period of death rate was from Feb 21 to May 7 .Using group A menigococcal polysaccharide vaccine made peak date of onset in advance,the case and death number of patients were more dispersive and no significant season characteristic. The peak date became to delay,season distribution became sigificant and case number was concentrated when the high morbidity appeared. Those characteristics of epidemic cerebrospinal meningitis were special in Zibo.