Objective:To survey and evaluate the effects of expanded programmed immunization of hepatitis B vaccine in newborns. Methods:A sero-epidemiology surveillance was conducted in infants aged 7-12 months in Huaian district of Huaian. Immunization history of hepatitis B vaccine (Hep B)was investigated and blood samples were collected at the same time. HBsAg,anti-HBs and anti-HBc was detected using chemiluminescence microparticle imunoassay (CMIA). HBsAg seropositive rate,anti-HBc seropositive rate,seroconversion rate and titer of anti-HBs were calculated and the influenced factors were analyzed using χ2 test or analysis of variance(ANOVA). Results:Twenty-three hundred and twenty infants were involved in the investigation. The timely first dose injection rate was 99.6%,and all the infants received the whole course vaccination. The HBsAg and anti-HBc seropositive rate was 0.13% and 2.1%,respectively the calculated protective rate of the Hep B was 93.4% and succession rate of blocking the maternal-infant transmission was 91.6%. The cause of the chronic HBV infection in the immunized infants was the failure of blocking maternal-infant transmission,the failure all happened in the infants with HBeAg positive mothers. The non-hyporesponsive rate was 26.3% in our surveillance population who immunized with 5 g Hep B,which was higher than other places using 10 g Hep B as the newborn immunization vaccine. Meanwhile the low birth weight infants had higher non-hyporesponsive rate than the normal birth weight infants. Conclusion:The standard vaccination rate of Hep B was very high and chronic HBV infection was very low in infants now. The chronic HBV infection in infants was mainly caused by maternal-infant transmission. The vaccine dose used in the infants should be added.