Abstract: Objective To explore the influencing factors of pregnancy-related anxiety in the first trimester of pregnancy. Methods We collected information on socio-demographic characteristics and environmental exposure among the pregnant women during 6 months of pre-pregnancy to the first trimester of pregnancy.The Pregnancy-related Anxiety Questionnaire was used to evaluate their mental health.Chi-square analysis and multiple stepwise regression analysis were performed to analyze the effect of socio-demographic and environmental factors on pregnancy-related anxiety. Results The rate of pregnancy-related anxiety was 23.2%(4 711/20 308)and the average score of the questionnaire was 20.57±5.04.Of the pregnant women younger than 25 years,28.4%had pregnancy-related anxiety.The pregnant women with the education of high school had the highest rate(27.0%).The pregnant women with rural residence had a higher rate(24.9%)than those with ruban residence registered.The results of stepwise multinomial regression analyses showed that factors significantly associated with pregnancy-related anxiety were smoking 6 months before the pregnancy(odds ratioOR=1.89,95% confidence intervalCI:1.35-2.65),alcohol drinking 6 months before the pregnancy(OR=1.81,95%CI:1.18-2.75), stress from work in early pregnacy(OR=2.26,95%CI:1.94-2.65),and unplaned pregnacy(OR=2.23,95%CI:2.08-2.60). Conclusion The factors of environmental exposure from 6 month before pregnancy to early pregnancy could have bad impact on the mental health and cause pregnancy-related anxiety in pregnant women.