To analyze the cognition status and the influencing factors of mother-to-child block of hepatitis B virus (HBV) of pregnant women. Methods: 1064 pregnant women who underwent initial antenatal examination in hospital were selected as research subjects from September 2021 to September 2022. Questionnaires of the knowledge on mother-to-child transmission of HBV were issued for these women. The demographic characteristics of these women and their cognition status of mother-to-child block of HBV were collected. Multivariate Logistic regression model was used to analyze the influencing factors of the cognition of mother-to-child block of HBV of the women. Results: The median score of knowledge on the prevention and treatment of mother-to-child transmission of HBV of the women was 7(3, 9) points. The awareness rates of the beginning time, the method, and the way to know about the knowledge of mother-to-child block of HBV of the women, and the available breastfeeding of the women with hepatitis B were all lower than 50%. The awareness rate (32.2%) of the available breastfeeding of the women with hepatitis B was the lowest. The median score of the attitude toward prevention and treatment of mother-to-child transmission of HBV of the women was 6 (5, 6) points. The acceptance rates of all the items about the attitude toward prevention and treatment of mother-to-child transmission of HBV of the women were higher than 80%. Multivariate Logistic regression analysis showed that the junior high school and below education level, farmers, and non-HBV carriers of the pregnant women were the factors influencing for their cognition of mother-to-child block of HBV (P<0.05). Conclusion: The cognition level about mother-to-child block of HBV of the pregnant women is low, and which is affected by the educational level, the occupation, and the HBV carrier status of the women. It is necessary to carry out targeted education on the related knowledge of mother-to-child block of HBV to improve the attitude and compliance of the women for preventing and treating their hepatitis B virus.