〔Abstract〕 Objective To investigate the trends in physical activity during pregnancy and analyze its influencing factors,providing foundational data for understanding and assessing the current status of physical activity among pregnant women in China. Methods Pregnant women who regularly attended antenatal check-ups at the Obstetrics Clinic of Shenzhen Second People's Hospital from February 2023 to August 2023 and intended to give birth in the obstetrics ward were selected as research subjects. The Chinese version of the pregnancy physical activity questionnaire (PPAQ) was administered during early to mid-pregnancy (14-27⁺⁶ weeks), late pregnancy (28-36⁺⁶ weeks), and from 37 weeks to delivery to investigate the trends and influencing factors of physical activity during mid to late pregnancy. Results Out of 400 subjects, 13 cases were excluded, and 50 cases dropped out, leaving 337 pregnant women who completed the survey. The rate of adequate physical activity was 42.13% during 14-27⁺⁶ weeks, 31.16 % during 28-36⁺⁶ weeks, and 36.20% from 37 weeks to delivery. Logistic regression analysis indicated that pregnant women with higher levels of education, higher household income per capita, and higher levels of knowledge and attitudes towards physical activity during pregnancy were more likely to meet the physical activity guidelines. The study also found that physical activity during pregnancy could shorten the duration of the first stage of labor. Conclusion Physical activity during pregnancy has a positive impact on pregnancy outcomes. Healthcare professionals should educate about the safety and benefits of physical activity during pregnancy, identify factors that promote or hinder physical activity, enhance pregnant women's self-efficacy in physical activity, and improve pregnancy outcomes.