To explore the analgesic effect of different dosages of nalbuphine combined with ropivacaine used in patients controlled epidural analgesia (PCEA) after cesarean section. Methods: 106 pregnant women who had accepted cesarean section between March 2019 and August 2020 were collected retrospectively. These women were divided into two groups according to their of anesthesia method after cesarean section. 54 women in the control group were treated with 0.2 mg/ml nalbuphine combined with ropivaca. 52 women in the observation group were treated with 0.4mg/ml nalbuphine combined with ropivacaine. The restlessness rate, the prolactin level, the motor block（Bromage) score, the sedation（Ramsay) score, the Ann comfort score (BCS), the visual analogue scale (VAS) score, and the values of various anesthesia indicators of the women at each time point after cesarean section were compared between the two groups. The incidence of adverse reactions from the cesarean section to discharge from hospital was counted. Results: The values of Ramsay score and VAS score of the women in the observation group at 12h, 24h and 48h after cesarean section were significantly lower than those of the women in the control group. The analgesia onset time (14.1±1.7min) and the first lactation time (26.7±2.3h) of the women in the observation group were significantly shorter than those (16.9±2.7min, 27.9±2.5h) of the women in the control group. The incidence of adverse reactions (3.9%) of the women in the observation group was significantly lower than that (16.7%) of the women in the control group. The agitation rate of the women in the observation group at each time point was significantly lower than that of the women in the control group. The level of prolactin of the women in the observation group at 24h, 48h and 72h after cesarean section was significantly higher than that of the women in the control group (all P＜0.05). Conclusion: After cesarean section, 0.4mg/ml nalbuphine combined with ropivacaine for PCEA can obtain satisfactory of sedation and analgesia, and can increase the prolactin level of the women.