Abstract: Objective To study immune effect of hepatitis B vaccine among children of 1-15 years old in Mianyang city,Sichuan province,and to provide basis for improvement of hepatitis B vaccination and booster immunization.Methods Using cluster random sampling method,children of 1-15 years old and having three times of hepatitis B vaccine vaccination were selected in Fucheng urban and rural areas.The titer of hepatitis B virsus surface antigen antibody(anti-HBs) was detected.Results Among the 1 503 children studied,the positive rate of anti-HBs was 59.9%(901/1503).The positive rate of anti-HBs was 58.9%(427/725)for the boys,60.9%(474/778)for the girls,61%(433/710)for the children living in urban area,and 59%for the rural children.The antibody positive rate was the highest among the children of one year old(95.3%,81/85),and that was lowest for the children of 6 years old(37.5%,24/64).The anti-HBs positive rate showed a declining trend in the children aged 1-6 years and the antibody positive rate was the lowest in the children of 6 years old.For the children of 1-3 years old,the titer of anti-HBs decreased most quickly.The small fluctuation of anti-HBs was observed in the chidren aged 4-6 years and then the rate began to rise slowly,but still lower than that of the 1-3 years old children.Anti-HBs titer was independent of gender and living areas of the children.Conclusion Vaccincation scheme and duration affect the immune effect of hepatitis B vaccine and serological monitoring should be conducted among the children 3 to 6 years after the 3 consecutive hepatitis vaccination for a timely booster immunization.