Objective To investigate the prenatal emotional disorder of the primipame and the related factors,and to analyze its influence on the delivery mode.Methods In the prospective cohort study,590 healthy primiparase were asked to complete a self-compiled questionnaires for their general social mental state,state-trait anxiety inventory(STAI)and self-rating depression scale(SDS).Results Questionnaires of 159 patients were selected and these patients were divided into the anxiety group(114 cases)and the control group(455 cases),the depression group(159 cases)and the control group(410 cases).The ratio of selective cesarean section in the anxiety group was significantly higher(45.61%,32.53%,X2=6.85,P＜0.01),while the successful trial of labor were less than that of the control group(19.35%,47.88%,X2=26.30,P＜0.01).The ratio of selective cesarean section in the depression group was significandy higher than that of the control group(46.54%,31.95%,X2=10.21,P＜0.01),while the successful trial of labor were less than that of the control group(31.76%.46.59%,X2=9.13,P＜0.01).Single-factor analysis showed that prenatal anxiety related to the following factors:fear of childbirth,worried about their children,knowledge for childbirth,high economic status,maternal age and their own economic situation.Conclusions Higher incidence and risk factors of anxiety or depression before delivery,such as advanced delivery age,bad economic condition,weak family support,worrying about the safety of babies and themselves,are found in our study.Prenatal emotional disorder would affect the quality of labor and delivery options,and lead the high risk of cesarean section.