Objective To observe the analgesic effects of patient-controlled intravenous analgesia (PCIA) and continuous infusion of morphine into epidural space(CIEA) after suprapubic transvesical prostatectomy. Methods Seventy-five patients undergoing suprapubic transvesical prostatectomy were randomly assigned to PCIA group,CIEA group and control group. In PCIA group, 2 0mg/h morphine as a recommended dose would be injected intravenously by the patient through a self-controlled analgesic delivery system in which another 1 mg morphine could be injected whenever patient felt pain until the pain relieved. The lockout time was 20 minutes. In CIEA group, 0 08 mg/h morphine was injected into epidural space. 50～75mg of pethidine was injected whenever the control group patients felt pain. VAS(vision simulate score), frequency and duration of bladder spasm, discontinuance time of bladder irrigation and BP were observed. Results The CIEA and PCIA group were superior to the control group with characteristics of stable analgesic effect, shorter duration and lower frequency of bladder spasm and shorter time of bladder irrigation(P0 05); but the PCIA group had longer gastrointestinal function recovery time(P