Background: Preconception care is an opportunity for detecting potential health risks in future parents and providing health behavior education to reduce morbidity and mortality for women and their offspring. Preconception care has been established in maternal and child health hospitals in Shanghai, China, which consists of health checkups, health education and counseling. This study investigated factors associated with the utilization of preconception care, and the role of preconception care on health behavior changes before conception among pregnant women and their partners. Methods: A cross-sectional study was conducted among pregnant women at three maternal and child health hospitals in Shanghai. The participants were invited to complete a self-administered questionnaire on the utilization of preconception care and health behavioral changes before conception. Results: Of the 948 recruited pregnant women, less than half (42.2%) reported that they had utilized preconception care before the current pregnancy. Unplanned pregnancy, unawareness of preconception care and already having a general physical examination were the main reasons for not attending preconception care. The two main sources of information about preconception care were local community workers and health professionals. Younger women and the multipara were less likely to utilize preconception care. Women who utilized preconception care were more likely to take folic acid supplements before conception [Adjusted Odds Ration (aOR) 3.27, 95% Confidence Interval (CI) 2.45–4.36, P < 0.0001]. The partners of pregnant women who had attended preconception care services were more likely to stop smoking [aOR 2.76, 95%CI 1.48–5.17, P = 0.002] and to stop drinking [aOR 2.13, 95%CI 1.03–4.39, P = 0.041] before conception. Conclusions: Utilization of preconception care was demonstrated to be positively associated with preconception health behavior changes such as women taking folic acid supplements before pregnancy, their male partner stopping smoking and drinking before conception. Future studies are needed to explore barriers to utilizing preconception care services and understand the quality of the services. Strategies of promoting preconception care to expectant couples, especially to young and multipara women, should be developed to further improve the utilization of the services at the community level.