Objective To discuss the effect of continuous phenylephrine infusion and single-dose phenylephrine injection on puerpera undergoing spinal and epidural combined anesthesia and the infant outcomes. Methods A total of 50 patients scheduled for selective cesarean section under combined spinal and epidural anesthesia were selected as the study subjects between July 2015 and June 2016. They were randomly allocated into two groups with 25 in each. Group CII underwent continuous phenylephrine infusion [0.5 μg/(kg·min)] immediately after anesthesia to adjust the blood pressure, while group CON accepted single-dose phenylephrine injection (50 μg) after anesthesia when systolic pressure was lower than 90 mm Hg (1 mm Hg=0.133 kPa) or when the decrease of mean arterial pressure (MAP) was higher than 20% of the base value. The infusion of phenylephrine was stopped after the fetus was taken out. MAP, cardiac output, cardiac index (CI) at the time when the patient went into the delivery room (T1), before anesthesia (T2), 1 minute after anesthesia (T3), 3 minutes after anesthesia (T4), 10 minutes after anesthesia (T5), and delivery (T6) were recorded. Blood gas analysis of fetal umbilical arterial blood was carried out and neonatal Apgar score was recorded. Results Hemodynamics was more stable in group CII compared with group CON. Heart rate at T4 and T5, and cardiac output at T5 and T6 in group CON were significantly lower than those in group CII (P<0.05). The neonatal umbilical arterial blood pH value, base excess and HCO3－ were all significantly lower, while partial pressure of carbon dioxide was significantly higher in group CON than group CII (P<0.05). Conclusion Compared with single-dose phenylephrine injection, continuous phenylephrine infusion has more stable hemodynamics, and exert less effect on maternal and infant outcomes for patients undergoing cesarean section under combined spinal and epidural anesthesia.