A total of 74 038 pregnant women who visited Nanjing Maternity and Child Health Care Hospital from January 1， 2017 to December 31，2019 were collected. Take their delivery outcomes （i.e. cesarean section and physiological birth） as the starting point， analyze the changes of cesarean section rate in three years， and take 2017 as the baseline to explore the effect of the policy in the year and the second year through multivariate analysis. In general， the cesarean section rate of 74 038 pregnant women who visited Nanjing Maternal and Child Health Hospital in three years showed a downward trend （linear trend chi square test， χ2 was 51.708， P < 0.001）. However， according to whether the pregnant women were old （≥ 35 years old） and whether they gave birth for the first time， it was found that only the cesarean section rate of the pregnant women who gave birth for the first time had a downward trend. In multivariate analysis， the cesarean section rate in 2018 was 0.890 times than that in 2017， and the cesarean section rate in 2019 was 0.869 times than that in 2017. To a certain extent， it can be explained and reflected that the management code of Nanjing high risk pregnant women management standard has an effect on controlling the cesarean section rate of first?time pregnant women under the age of 35， but it has no effect on high?risk pregnant women， further research and policy improvement are needed.