Ｏｂｊｅｃｔｉｖｅ　To investigate the efficacy and safety of differen dose hydromorphone on cesatrean section administered epidurally.　Methods　Sixty patients undergoing cesatrean section under epidural anesthesia were randomly divided into three groups, group A, group B and group C(n=20). The patients in group A, group B and group C were injected separately 0.1, 0.2 mg and 0.3 mg hydromorphone combined with 5 ml normal saline 10 min before the end of operation through epidural space. The VAS scores were recored at 3, 6, 12 h and 24 h postoperatively. At the same time, the number of patients requiring analgesic at 24 h and side effects were recorded.　Results　The VAS scores in group C was lower than that in group A and group B, and group B was lower than group A (P＜0.05) at 6, 12 h and 24 h postoperativly. The number of patients requiring analgesic at 24 h in group C(2 cases) was significantly less than that in groupA(8 cases) (P＜0.05). The side effects were no significant difference(P>0.05).　Conclusions　Different dose epidural hydromorphone applied to cesarean section for postoperative early analgesia can provide satisfactory analgesic effect, and the dose in 0.3 mg was better.