Objective To investigate the effect of elective cesarean section prenatal hormones on the full-term infants respiratory distress syndrome (RDS) incidence and complications. Methods The 2 606 cases of survival of full-term infants born in Huzhou Maternal and Child Healthcare Hospital between January,2010 to January,2011.Cases were divided into two groups:dexamethasone was used for a course more than 24 hours before the baby was born as observation group;the other group was the control group without dexamethasone.And the two groups were divided into three groups,depending on gestational age,respectively.which were gestational age 37~37⁺⁶ weeks,gestational age 38~38⁺⁶ weeks,gestational age 39~40 weeks.The different gestationgal age of the incidence of RDS and complications were compared. Result The incidence of RDS in the observation group was significantly lower than the control group,and the incidence in the different gestational was different,and the condition of the observation group was light compared with the control group.Conclusion 37~38 weeks cesarean section prenatal use of hormones is worth promoting.