Abstract: Objective :To Compare the effect of postoperative analgesia on Sufentanil with different doses, after surgical operation on pelvic tumor. Methods :Sixty patients of ASA I-flgrade,scheduled to undergo pelvis tumor operations, were randomly divided into three groups, i.e. Group Fentanyl (F 0.3ug/kg/h), Group Sufentanil I (S1, the ratio with Fentanyl is 1:10) and Group Sufentanil (S2, The ratio with Fentanyl is 1:8). The following parameters were recorded: heart rate, breath, VAS, Sp02, calm score and side effect at 4 h, 8 h, 12 h, 24 h, 48 h and 72 h after surgery. Results :No significant difference was found in heart rate, Spot and breath bamong the three groups (P>0.05). No significantly difference were found in VAS between group F and group S1 (P>0.05), but the VAS was decreased significantly in group S2 (P<0.05). The calm scwas higher in group S1 and S2 than in groupF. No serious side effecet was found in the three groups. Conclusions :The effect of Sufentanil is better than that of Fentanyl in application of postoperative analgesia for pelvic tumor.