Objective: To compare the effects of alone and combined administration of nalbuphine and sufentanyl for patient-controlled intravenous analgesia (PCIA) after caesarean section. Methods: From June 2017 to December 2017, 90 women undergoing cesarean section in the Sixth Hospital Affiliated to Shanxi Medical University were selected.They were divided into three groups(with 30 cases in each group) using a random number table: sufentanyl 1.5μg/kg group (group S), nalbuphine 2.0mg/kg group (group N) and nalbuphine 1.0mg/kg+ sufentanyl 1μg/kg group (group NS). In each group tropisetron 6 mg was added, and PCIA solution was then diluted to 10mL in normal saline.Postoperative vital signs, visual analogue scale (VAS) score, the highest Ramsay sedation score, number of self-control analgesia and the occurrence of side effects within 24h after operation were recorded. Results: The highest VAS score within 24h after surgery had statistically significant difference among the three groups [group N (2.66±1.09)points > group S (1.45±0.57)points > group NS (0.90±0.55)points](F=40.11, P<0.05). The Ramsay sedation score among the three groups had no statistically significant difference [group S (2.34±0.61)points, group N (3.13±0.63)points, group NS (2.60±0.72)points] (F=11.00, P>0.05). The number of controlled analgesia among the three groups had no statistically significant difference [group S (0.76±0.69), group N (2.93±0.87), group NS (0.54±0.57)] (F=101.11, P>0.05). The incidence rates of adverse reactions of the three groups were 26.66%(8/30), 16.67%(5/30) and 6.66%(2/30), respecyively, the difference was not statistically significant (P>0.05). Conclusion Combination of nalbuphine and sufentanyl has more significant effect of PCIA after cesarean section than either of the drugs use alone, which is worthy of clinical promotion.