Background: In 2016, Qinghai Province and the Asian Liver Center of Stanford University in the United States cooperated to carry out a one-year project of hepatitis B mother-to-child blockade and post-immunization serological test in our province. Through this study, we evaluated the current situation of hepatitis B maternal and infant blockade and the effect of maternal and infant blockade in multi-ethnic areas of Qinghai Province. Methods: From May 1, 2016 to April 30, 2017, all pregnant women who gave birth in Qinghai Province were screened for HBsAg. For pregnant women who were screened for HBsAg positive, the medical staff had a detailed understanding of the history and treatment of hepatitis B, and provided scientific nutritional support and guidance. Free hepatitis B immunoglobulin (100 units) injections were given to newborns born to HBsAg-positive mothers within 12 hours after birth, and three doses of hepatitis B vaccination were given. All newborns born to HBsAg-positive mothers were followed up from 1 to 3 months after complete immunization of HBIG and HepB. The County (district) CDC was responsible for rapid fingertip blood screening, screening for HBsAg-positive children, collecting 3ml of venous blood for quantitative detection of HBsAg.Results: During the study period, 61381 pregnant women were hospitalized, 6027 (97.79% ) pregnant women were screened for HBsAg. 1912 pregnant women were detected positive for HBsAg, with a positive rate of 3.19%. The HepB vaccine rate was 97.11% in live infants within 24 hours. The vaccination rate of hepatitis B vaccine was 94.78% and the injection rate of HBIG was 97.15% in 12-hour live delivery children of HBsAg positive mothers. A total of 864 newborns born to HBsAg positive mothers were followed up. Fast fingertip blood test was performed 1-3 months after HBIG injection and whole course hepatitis B vaccination. The positive rate of HBsAg was 5.21%. 34 positive serum samples were detected by chemiluminescent immunoassay in the laboratory of provincial CDC. The coincidence rate of HBsAg positive was 82.35%, and that of HBV DNA positive was 79.41%. Fifty-seven children with HBV surface antibody negative were detected and vaccinated with HBV vaccine free of charge in the whole course according to the national immunization program. Conclusion: The infection rate of hepatitis B among women of childbearing age in Qinghai province is 3.19%, and the blocking rate of mother and infant is 94.79%. It is still necessary to strengthen the injection of hepatitis B vaccine and HBIG for positive mothers and children. Keyword: Hepatitis B, Mother to child blocking, Evaluation of the effect Corresponding Author. have equal contributions to this article. Author SummaryThis study revealed for the first time the infection rate of hepatitis B virus among women of childbearing age of different nationalities in Qinghai-Tibet Plateau through screening of pregnant women in hospital, blocking of mother and infant, and following-up of serum test after immunization. To evaluate the combine...