Abstract: Objective To investigate the prevalence of hepatitis B virus (HBV) infection in pregnant women and the risk factors for Intrauterine infection of HBV among pregnant women in Xiamen. Methods Total 1 064 pregnant women were included in this study. A questionnaire was performed to collect the general information of the subjects and HBV infection status was tested on the first day when they came to the hospital. Then HBsAg positive pregnant women were selected and followed until delivery. We collected their cord blood and placenta tissue when they delivery. HBsAg and HBV DNA in cord blood and HBsAg in placental tissue were detected. Chi-square test and the non-conditional Logistic regression analysis were conducted to investigate the correlation between HBV intrauterine infection and risk factors. Results 179 out of the 1 064 pregnant women were HBsAg positive. The infection rate was 16.8%. 34 out of 179 HBsAg positive pregnant women were found intrauterine transmission with a rate of 19.0%. The risk factors for the occurrence of HBV intrauterine transmission were placenta HBsAg positive (OR=5.123,95% CI:1.422-18.413), mothers with hepatitis B e antigen(HBeAg) positive (OR=4.619,95% CI:1.225-17.534) and overweight(OR=3.343,95% CI:1.233-9.092), respectively. Conclusions Placenta HBsAg positive, mothers with HBeAg positive and overweight are independent risk factors for the occurrence of HBV intrauterine transmission.