Abstract: Objective To compare the efficacy of gonadotropin-releasing hormone agonist(GnRH-a)and levonorgestrel releasing intrauterine system(LNG-IUS)in the treatment of adenomyosis(AM). Methods A total of 80 patients with AM were selected and divided into observation group and control group according to the computer random number method, with 40 cases in each group. Observation group was given LNG-IUS, and control group was given GnRH-a for the treatment. The levels of clinical indexes ［uterus volume, endometrial thickness, menstrual blood volume, Visual Analogue Scale(VAS)score for dysmenorrhea, serum cancer antigen 125(CA125), positive rate of endometrial antibody(EMAb)］ and sex hormones ［luteinizing hormone(LH), follicle-stimulating hormone(FSH), estradiol(E₂)and progesterone(P)］ were observed in the two groups before and after treatment. And the clinical efficacy, incidence of adverse reactions and treatment costs were compared between the two groups. Results Compared with before treatment, the uterus volume was decreased after 6 months of treatment, and the menstrual blood volume was decreased, and the endometrial thickness, VAS score for dysmenorrhea, serum CA125 level and EMAb positive rate were decreased(P<0.05), the changes degree of above indicators in the observation group were more - than that in the control group except for CA125(P<0.05). After 6 months of treatment, the serum levels of LH, FSH, E₂ and P in the control group were lower than those before treatment(P<0.05), but showed no significant differences in the observation group compared with those before treatment(P>0.05). There was no significant difference in the total effective rate between the two groups(P>0.05), and the incidence rate of adverse reactions and treatment costs in the observation group were lower than those in control group(P<0.05 or P<0.01). Conclusion Compared with GnRH-a, LNG-IUS has better effect in improvement of uterus and menstrual conditions, and has no significant effects on sex hormone secretion. Meanwhile, it is safe and economic, and has fewer adverse reactions and lower treatment costs.