Objective: To observe the effect of prophylactic intravenous injection of norepinephrine on maternal blood pressure, heart rate and neonate during cesarean section under lumbar anesthesia. Methods: A total of 100 single full-term parturients scheduled for cesarean section under lumbar anesthesia were divided into two groups with 50 cases each according to random number table method. Group NE was injected norepinephrine and group C was for the control group. After lumbar anesthesia successful, patients were placed in supine position immediately, and the operating bed was tilted to the left at 15°. Hydroxyethyl starch was infused rapidly and synchronously, and group NE received boluses of norepinephrine 8 μg (2 μg/mL) and the same 4 mL capacity of normal saline for group C. SBP and HR were observed and recorded every minute from supine position after subarachnoid administration to fetal removal. The incidence of adverse reactions such as maternal hypotension, hypertension, bradycardia and nausea and vomiting were also recorded. The case and frequency used additional norepinephrine, Apgar scores at 1 minute and 5 minutes after fetal removal, and umbilical cord blood gas values were also recorded. Results: SBP in group NE reached the peak at the 3rd minute after intrathecal administration, and reached the lowest point at the 9th minute, but the low values were occurred at the 6th, 10th and 14th minute in group C. Compared with group C, SBP in group NE was more stable (P<0.05). HR in group NE showed a downtrend after administration, and HR reached the lowest point at 4th minute and the highest at the 9th minute. HR in group C increased to the highest level at the 6th min after administration. There was no significant difference in the incidence of hypertension and sinus bradycardia between the 2 groups (P>0.05), but the incidence of hypotension and nausea and vomiting in group NE were significantly lower than those in group C (P<0.05), and the number and frequency of additional NE in group NE were significantly lower than those in group C (P<0.05). There was no significant difference in umbilical artery and vein blood gas analysis and Apgar scores at 1 min and 5 min between the 2 groups. Conclusion: Prophylactic intravenous injection of norepinephrine 8 μg could effectively reduce the occurrence of hypotension and nausea and vomiting after lumbar anesthesia in parturients, and has no adverse effects on newborns.