Abstract: Objective: To investigate the pregnant women's dietary, living style, weight control knowledge in the second trimester of pregnancy. Methods: A cross-sectional study was conducted, and 308 pregnant women in obstetric clinic of tertiary Grade A were surveyed using a questionnaire. Results: The pregnant women's dietary structure was not balanced and the single type of food intake was higher or lower than the recommended intake in half of pregnant women. About 79.2% women continued to work after pregency and 52.9% women's daily activities was mild. About 47.1% women never exercise, and only 12.7% of them took part in physical exercise every day. Among women who participated exercise, only 12.9% women whose average exercise time reached to 1h/d. The error rates of the three questions about weight control knowledge were between 42.5%~59.1%. About 45.5% women gained superstandard weight in the first trimester of pregnancy. Conclusions: In clinical practice, the general problems of women in the second trimester of pregnancy included mistaken idea about life style and knowledge deficit of weight control. Health education should be designed to pay more attention to improve women's compliance. We should formulate specific and workable gestational weight intervention project so as to effectively control their weight.