Abstract: Objective To analyze the characteristics of adverse event following supplementary immunization activity (SIA) of Hepatitis B in Nanchang during 2009-2010, understand the safety of Hepatitis B vaccine and explore measures to reduce the adverse event. Methods The descriptive epidemiology analysis was conducted on related indexes. Results Twenty three adverse events were reported among the children aged 8-15 years in SIA during this period, the incidence rate was 1.72/lakh dose. Among these events, 12 were mild reactions, 10 were serious reactions and most of them were allergic reactions. Up to 69.57% of the adverse events occurred within 24 hours after immunization. Most cases were cured. Conclusion The incidence of adverse event following SIA of hepatitis B was low in Nanchang. It is necessary to strengthen the surveillance of adverse event following the vaccination among the vaccinated children and improve the prevention and response of adverse event following immunization.