Objective. To study the effect of Mirena intrauterine device (IUD) on endometrial thickness, life quality score, and curative effect in patients with perimenopausal abnormal uterine bleeding. Methods. Eighty patients with perimenopausal abnormal uterine bleeding cured from January 2020 to December 2021 were enrolled as the object of study. According to random number table, the patients were classified into the study (
n
=
40
) and control (
n
=
40
) groups. The control cases were cured with medroxyprogesterone. The study cases were cured with Mirena IUD. The effective rate of clinical therapies was evaluated after 3 months of treatment. The endometrial thickness, menstrual volume score, and life quality score (WHOQOL-BREF) was measured after 1 month, 2 months, and 3 months of treatment. Results. The effective rate of patients with Mirena IUD for 3 months was higher compared to the control group (
P
<
0.05
). The endometrial thickness and menstrual volume scores of study cohort after 1 month, 2 months, and 3 months following treatment were remarkably lower than those before treatment (
P
<
0.05
) and were considerably lower than those of control cohort (
P
<
0.05
). The hemoglobin level of the studied cases after 1 month, 2 months, and 3 months after therapy was remarkably upregulated (
P
<
0.05
) and was greatly higher compared to the controlled cases (
P
<
0.05
). After 3-month treatment, the WHOQOL-BREF score of the study group was higher compared to the control group (
P
<
0.05
). Conclusion. The Mirena IUD is far more effective in the treatment of perimenopausal abnormal uterine bleeding and is helpful in reducing the thickness of the endometrium. Patients’ menstrual flow can be controlled, and anemia can be corrected; thus, patients improve their quality of life and health status and can be considered for further promotion.