〔Abstract〕 Objective To clarify the etiological association between different delivery modes and developmental behavior of preschool children. Methods A cross-sectional survey was conducted. A questionnaire survey was conducted on 27 987 preschoolers aged 3 to 6 years old. Questionnaires collected parents' basic demographic characteristics, basic information of children, their lifestyle and so on. The Age and Stages Questionnaire-third edition(ASQ-C) was used to evaluate developmental behaviors of preschool children, excluding children whose parents did not agree to do developmental behavior assessment and did not complete ASQ-C assessment. Finally, a total of 14 634 children completed developmental behavior assessment. Results The detection rates of communication(CM), gross motor(GM), fine motor(FM), problem solving(CG) and person-social(PS) function retardation in preschool children were 22.1%, 19.4%, 18.3%, 23.8% and 24.1%, respectively. After adjusting for confounding factors, compared to women with vaginal delivery, cesarean section with medical indications was positively correlated with gross motor retardation of preschool children(OR=1.14, 95%CI:1.04～1.25) and person-social retardation(OR=1.10, 95%CI:1.01～1.20). There was a positive correlation between cesarean section without medical indications and gross motor(OR=1.16, 95%CI:1.03～1.30), fine motor(OR=1.22, 95%CI:1.08～1.37) and problem solving(OR=1.20, 95%CI:1.07～1.34) retardation in preschool children. Conclusion Compared with vaginal delivery, cesarean section is associated with developmental behavioral delay in preschool children.