Abstract： Objective To investigate the trend in birth weight of term infants delivered in Miyun Hospital in recent ten years, and its relationship with cesarean section rate, to provide evidence for health care during pregnancy and lowering the cesarean section rate. Methods Singleton term live-birth newborns in Beijing Miyun Hospital from January 1, 2000 to December 31, 2009 were admitted into this study. Trends of birth weight, microsomia rate and cesarean section rate were analyzed. Results (1) There were 14 716 singleton term live-birth newborns delivered in the tenyear period, among which 7642 males and 7074 females with the proportion of male and female of 1.08 : 1. One thousand seven hundred and seventy-three (12.0％) microsomia were delivered, and the number of low birth weight infants was 180 (1.2％). (2) The birth weight of term infants was from 1200 g to 5850 g and the average birth weight was (3422±447) g. The average birth weight of each year increased, and the differences among each year showed statistical significance (F= 15. 337,P＜0.01). (3) The percentage of microsomia of each year increased, and the differences among each year also showed statistical significance (x2= 125. 285, P＜0. 01). (4) The cesarean section rate increased from 49.9％ in 2000 to 57.1％ in 2009 with statistical difference (x2 =180. 883, P＜0.01).(5) The cesarean section rate increased with the average birth weight of the singleton live-birth term infants in the 10 years from 52.2 ％ in those ＜2500 g to 85.4 ％ in those 4500 g～, and the differences had statistical significance (x2 =518. 519, P＜0. 01). Conclusions Cesarean section rate had close correlation with birth weight in term birth infants. It is suggested that prenatal care should be strengthened and nutrition guidance during pregnancy should be paid more attention.