A 12-year-old girl who has been on her period for 20 days and still hasn’t cleaned up is usually suffering from dysfunctional uterine bleeding, which can be treated by medicines such as estradiol valerate tablets and estradiol benzoate tablets after excluding other abnormal possibilities. Dysfunctional uterine bleeding is abnormal uterine bleeding caused by the dysfunction of the reproductive endocrine axis. The risk of dysfunctional uterine bleeding is higher in adolescent girls and menopausal women, mainly due to the imperfect development of the hypothalamic-pituitary-ovarian axis or the decline of ovarian function, which is often manifested as irregular abnormal uterine bleeding and menorrhagia. Patients can use estrogenic drugs such as estradiol valerate tablets and estradiol benzoate tablets for treatment, which are suitable for adolescent patients with prolonged bleeding time and large amount of bleeding, and can play a role in stopping bleeding. The 12-year-old girl has 20 days of menstrual period is still not clean, it is recommended to go to the hospital in time for examination and treatment, in addition to the blood meridian, may also be other diseases caused by the symptoms, need to identify the cause of a clear diagnosis, for standardized treatment.