Objective: To study the effect of diclofenac suppository in oocyte retrieval of IVF-ET. Study Design: 1176 patients with informed consents were enrolled into this prospective randomized controlled study. The setting was an IVF-ET program at the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China. According to the analgesic drug use, the patients were randomly divided into pethidine group (573 cases) and diclofenac suppository group (603 cases). The data of vital signs, common adverse reactions, severe adverse events and pain degree in oocyte retrieval were collected. The IVF-ET outcomes were also compared. Results: The post-operation pressure and pulse were lower in pethidine group than in diclofenac suppository group (both P<0.001).The rest vital signs were not statistically different (all P>0.05). Common adverse reactions in diclofenac suppository group were relative less (all P<0.05). Pain degree between the two groups was not statistically different (P=0.304). IVF-ET outcomes were also not statistically different (all P>0.05). There were 3 cases serious abdominal bleeding with shock in the diclofenac suppository group. Conclusion: Using diclofenac suppository in oocyte retrieval analgesic had a good effect. And there was no adverse effect in the IVF-ET outcome. But we should pay close attention to the probability of serious abdominal bleeding.