Objective: To compare the efficacy of ondansetron on the prevention of postoperative nausea and vomiting(PONV) under different general anesthesia methods. Methods:Two hundreds and forty patients undergoing gynecologic laparoscopy with different maintain methods of general anesthesia were randomly divided into six groups:sevoflurane group(group A1), sevoflurane with ondansetron group(group A2), propofol group(group B1), propofol with ondansetron group(group B2), propofol combined sevoflurane group(group C1), and propofol combined sevoflurane with ondansetron group(group C2), 40 patients in each group. Ondansetron of 8mg was given intravenous at 5 min before the end of surgery. Observed the nausea and vomiting situation after tracheal extubation in different periods(0~4h, 4~8h, 8~12h, 12~16h, 16~24h). Results:① In group B1 and group C1, the incidences of nausea reduced significantly compared with those in group A1 in 24 h(P < 0.05). In group A2, B2 and C2 compared with those in group A1, B1 and C1 respectively, the incidence of nausea was significantly lower in 0-12 h(P < 0.05), while within 12-24 h the incidence of nausea did not reduced obviously. ② In group B1 and group C1, the incidences of vomiting reduced significantly compared with those in group A1 in 24 h(P < 0.05). Compared with those in group A1, B1 and C1 respectively, the incidence of vomiting in group A2, B2 and C2 was significantly lower in 24 h(P < 0.05). Conclusion:Compared with the anesthesia methods of propofol or propofol combined sevoflurane, the sevoflurane anesthesia method has a more susceptible to PONV in patients. Ondansetron doesn’t have the same efficacy in PONV under different general anesthesia methods, and the treatment of nausea was better than vomiting within 24h after surgery. What’s more, ondansetron has better treatment of PONV caused by sevoflurane anesthesia method.