OBTECTIVE:To compare th e clinieal effect of postoperative patient-controlled analgesia with epidural tr amadol, intravenous fentanyl METHOD:The 75 cases of abdomina l surgical patients were randomly divided into 3 groups:25 cases epidural trame dol (group TE),25 cases intravenous tramadol (group TI) and the others intraveno us fentanyl (group FI),with a Abbot 13960-36 PCA pump in the loading-continuous- PCA model. RESULTS:①in the postoperative 4, 24 and 48 hours,the a mount of drugs,the total deliveries,the ratios of deliveries to demands (D/Drati o) and VAS scores used in group TE and TI were similer (P＞0.05).The amount of d rugs used in each group was TI＞FI,TE＞FI,P＜0.05,but VAS scores were similar.② The incidence of nausea was group TE 12%,group TI 8% and FI 12%;the incidence of vomiting was 4% to 4% to 8% separately.Respiratory depression had been observed in group FI 4%. CONCLUSION:Results indicated that tramadol is safe and effective for the postoperative patient-controlled ana lgesia.The effects of PCEA were similar.