Objective: To investigate the prevalence of hepatitis B virus (HBV) carriage among pregnant and lying-in women in Cangnan County, Zhejiang Province from 2011 to 2022 and identify the influencing factors, so as to provide insights into the guidance of healthcare among HBV carriers during pregnancy. Methods: A total of 34 403 women delivered in The Third People's Hospital of Cangnan County from January 2011 to July 2022 were enrolled, and their demographics, HBV carriage and pregnant outcomes were collected. The prevalence of HBV carriage was analyzed among pregnant and lying-in women, and factors affecting HBV carriage were identified using a multivariable logistic regression model. Results: A total of 34 403 pregnant and lying-in women were enrolled, with a median age of 27.00 (interquartile range, 7.00) years, and including 8 118 floating populations (23.60%). The overall prevalence of HBV carriage was 3.44%, and the prevalence of HBV carriage was 1.59% from 2011 to 2014, 4.08% from 2015 to 2018 and 6.86% from 2019 to 2022, appearing a tendency towards a rise (P<0.05). Multivariable logistic regression analysis identified estimated age of delivery (20-24 years, OR=1.832, 95%CI: 1.037-3.235; 25-29 years, OR=2.404, 95%CI: 1.372-4.214; 30-34 years, OR=2.914, 95%CI: 1.656-5.129; 35-39 years, OR=3.116, 95%CI: 1.741-5.576; 40 years and older, OR=2.358, 95%CI: 1.145-4.858), floating population (OR=0.670, 95%CI: 0.574-0.782), scarred uterus after cesarean section (OR=1.228, 95%CI: 1.076-1.521) and year of delivery (from 2015 to 2018, OR=2.504, 95%CI: 2.143-2.926; from 2019 to 2022, OR=4.425, 95%CI: 3.779-5.182) as factors affecting HBV carriage among pregnant and lying-in women. Conclusions The prevalence of HBV carriage rate appeared a tendency towards a rise among pregnant and lying-in women in Cangnan County from 2011 to 2022. Estimated age of delivery, floating population, year of delivery and scarred uterus after cesarean section are factors affecting HBV carriage.