In May 2018, Nanjing Health Committee issued the "Nanjing high risk pregnant women management standard"， this paper analyzes the change trend and related influencing factors of delivery mode of pregnant women in Nanjing Maternity and Child Health Care Hospital from 2017 to 2019 from three stages: before the implementation of the policy, at the beginning of the implementation and one year after the implementation, so as to provide research evidence and decision support for the effective control of the current high cesarean section rate. A total of 74038 pregnant and lying in women who visited our hospital in three years were collected by cluster sampling. The data included age, length of hospital stay, diabetes and hypertension, times of pregnancy and mode of delivery. T test, analysis of variance, chi square test and logistic regression model were used for statistical analysis. The results showed that the cesarean section rate of pregnant and lying in women in our hospital showed a downward trend from 2017 to 2019 (linear trend 2 = 51.708, P < 0.001). After classifying the pregnant and lying in women, we found that only the cesarean section rate of primiparas under 35 years old had a downward trend (H = 42.522, P < 0.001). Logistic regression showed that age and length of hospital stay were positively correlated with different types of cesarean section, and the influencing factors of different types of cesarean section were also different. The implementation effect of "Nanjing high risk pregnant women management standard" can not be attributed to the decrease of cesarean section rate in general, but should be more accurately attributed to the decrease of cesarean section rate in primipara under 35 years old. For the control of cesarean section rate, we need to continue to pay attention to and control, and use fine management and improve midwifery technology to effectively control the cesarean section rate.