Abstract: Hepatitis B virus was prevalence in China; most children under 15 years old suffered it by mother-to-infant transmission (MTCT). Researches showed that vaccinating hepatitis B vaccine and Hepatitis B hyper-immune globulin (HBIg) could interrupt 95%MTCT. Though there were 10%~30% of HBs Ag (+) pregnant women blocking MTCT failed. The failing reasons and influence factors were not clear. This study summarized relating factors including pregnant women infection status, HBV-DNA in mothers' blood, delivery way, infant feeding way, special infant, implementation of National Integrated Prevention of Mother-to-infant Transmission of HIV, Syphilis and HBV (i PMTCT), and expected to provide references for latter study on integrating MTCT of HBV.