Abstract: Objective To explore the effects of levonorgestrel-releasing intrauterine system on pain, serum carbohydrate antigen 125(CA125)and sex hormones in adenomyosis patients with dysmenorrhea. Method A total of 118 adenomyosis patients with dysmenorrhea were selected and divided into control group and observation group according to random number table method, with 59 cases in each group. The control group was treated with progesterone, while the observation group was treated with levonorgestrel-releasing intrauterine system. The changes in the degree of dysmenorrhea pain, endometrial thickness and uterine volume, serum CA125, estradiol(E₂), follicle-stimulating hormone(FSH)and luteining hormone(LH)were compared and analyzed in the two groups. Results After treatment, the degree of dysmenorrhea in the observation group was significantly lower than that in the control group(P<0.05), the endometrial thickness and uterine volume in the observation group were significantly smaller than those in the control group(P<0.05), the level of serum CA125 in the observation group was significantly lower than that in the control group, and the level of E₂ was significantly higher than that in the control group(P<0.05). There were no significant differences in FSH and LH levels between the two groups(P>0.05). Conclusion Levonorgestrel-releasing intrauterine system for treatment of dysmenorrhea patients with perimenopausal adenomyosis can effectively relieve the pain, improve the intrauterine membrane thickness and uterine volume, and regulate the level of sex hormones, and it has higher safety.