Abstract: Objective Understand the reference range of fetal birth weight in clinical practice,so as to provide a basis for further reducing the rate of cesarean section and improving the quality of perinatal health care services.Methods Full-term singleton live births and their mothers delivered from January 1,2017 to December 31,2017 in Guangdong Medical Certificate Management Information system were selected as the object of study.The relationship between the distribution of birth weight,the incidence of macrosomia and the rate of cesarean section were analyzed.Results The cesarean section rate was 30.6%(540 641/1 766 153).The average birth weight of newborns was(3194±402) g.The incidence of low birth weight(<2500 g) was 2.8%(49 672/1 766 153),and the macrosomia(birth weight≥4000 g) incidence rate was 3.2%(55 893/1 766 153) Birth weight between 2500 to 3499 g accounted for 73.9%(1 304 677/1 766 153).Birth weight between 3500 to 3999 g accounted for 20.2%(355 911/1 766 153).Compared with the newborn birth weight of(2500-3499) g,the cesarean section rate of low birth weight group was higher than that of the control group.The difference was statistically significant(P<0.001),when the birth weight was≥3600 g,the cesarean section rate was higher than the control group,and the cesarean section rate increased with the increase of birth weight,and the difference was statistically significant(P<0.001).Conclusion Lower or higher birth weight of the fetus affects the choice of delivery mode,and the continuous monitoring and management of in-hospital and out-hospital health promotion and body weight growth during pregnancy should be strengthened.