Based on a 8-year surveillance data, a factor analysis theory was used to analyze the 12 risk factors influencing the epidemicity of epidemic cerebrospinal meningitis. The results showed that the first sixth risk factors were the rate of carrying meningococci A and B in the population, relative air humidity in January, morbidity rate in January, vaccination rate before epidemic, and the titre of antibody. Although the incidences of epidemic cerebrospinal meningitis are scattered, the risk factors influencing the epidemicity did not disappear. It is important to use meningococci A vaccine continuously and widely to strengthen the surveillance among migrated population and population at high risk.