Abstract: Objective：To investigate the clinical efficacy and side effects of levonorgestrel-releasing intrauterine system in the treatment of endometriosis（EMs）after conservasive laparoscopic surgery. Methods：seventy women of EMs with complain of dysmenorrhea were recruited， they were devided into two groups，35 women were placed LNG-IUS， 35 women were given GnRHa therapy. In addition，33 women of EMs who were given non-steroidal anti-inflammatory drug therapy after surgery were recruited as control group. The average followed up period was 14 months. The mean visual analogue scale（VAS）scores of their dysmenorrhea， serum CA125 levels，recurring rate among the three groups and between pretherapy and post-therapy were compared.Also the side effects of LNG-IUS，the continuation rate and the degree of satisfaction were evaluated. Results：In LNG-IUS group，significant difference（P＜0.05） existed in VAS scores at the end of 3 months，6 months and 1 year treatment when compare with the preoperative situation. After one year's treatment，The VAS scores in LNG-IUS group were significantly lower than control group and GnRHa group（P＜0.05）. There was no significant difference（P＞0.05） in serum CA125 between LNG-IUS group and GnRHa group at the end of 6 months treatment，but significant decrease（P＜0.05） existed when comparison was made between LNG-IUS group and control group. After one year's treatment，the recurrence rate of LNG-IUS group and GnRHa group were obviously lower than the control group（P＜0.05），there was no obvious difference between LNG-IUS group and GnRHa group（P＞0.05）. After one year's treatment，there were 25.0% of the patients with irregular uterine bleeding in LNG-IUS group，54.5% of the subjects were very satisfied or satisfied with the treatment，and the continuation rate of LNG-IUS was 94.0%. Conclusions：Placing LNG-IUS as an accessory treatment for patients with EMs after conservasive laparoscopic surgery is effective，with high degree of satisfaction and high continuation. Irregular uterine bleeding is the main side effect.

Key words: Endometriosis, Levonorgestrel, Intrauterine devices, Laparoscopes, Dysmenorrhea