Abstract: ObjectiveTo study the long-term efficacy of immunization of hepatitis B vaccine and its influential factors on it.MethodsChildren aged 1～19 years old among 8 villages were chosen for the pilot study in Zhengding County.Sera were collected for detecting HBsAg,anti-HBs and anti-HBc by solid-phase immunoassay assay.The results database were analyzed by Epi Infoand SAS software.ResultsThe average HBsAg positive rate of children aged 1～19 years descended from 9.48% to 1.46% after immunity,and the anti-HBc positive rate descended from 33.81% to 5.94%.Anti-HBs positive rate was 62.13%,significantly higher than that before the immunization.HBsAg positive rate of the children who vaccinated the entire journey was the lowest(0.35%).HBsAg positive rate of the children whose mothers HBsAg positive was 33.5 times than that of those whose mothers HBsAg negative.ConclusionThe efficacy of hepatitis B vaccine after 19 years immunization was still very excellent.The key influencing factors were the mother HBsAg carrier situation and inoculation history of hepatitis B vaccine.