Background: Rubella infection in pregnant women can result in serious effects, such as miscarriages, stillbirths, and congenital rubella syndrome (CRS). However, very little is known about the rubella seroprevalence among pregnant women in China. Methods: This is a cross-sectional and hospital-based study. From June 2016 through March 2017, a total of 324 serum samples from healthy pregnant women were collected in the Shunyi Women and Children's Hospital of Beijing Children's Hospital. Rubella-specific IgG antibody was determined by ELISA (Euroimmun, Lubeck, Germany) kits. International assigned cut-off values of >= 10 IU/ml were used to assess the percentage of pregnant women with protective IgG concentrations. Results: The total rate of protected individuals was 83.3% (95% CI: 78.9%-87.0%). The protective rates of pregnant women in 17-26 years group, 27-36 years group and 37-46 years group were 84.0% (95% CI: 75.3%-90.1%), 81.9% (95% CI: 74.9%-87.4%) and 84.9% (95% CI: 75.8%-90.9%) respectively. No significant difference in protective rates among the three age groups was found (P = 0.83). There were also no statistically significant correlations between protective rates and gravidity (P = 0.84), parity (P = 0.84), birth place (P = 0.16), residence area (P = 0.58), education (P = 0.40) or occupation (P = 0.65). Conclusions: Despite the generally low vaccination coverage for rubella, most of Chinese pregnant women had potent rubella immunity. However, at least 16.7% of pregnant women were susceptible to rubella, which suggested rubella immunization in Chinese women at or before child-bearing age.