If a 15-year-old girl has her period twice a month, it is usually due to abnormal uterine bleeding caused by immaturity of pituitary axis and immaturity of ovarian function, which is a manifestation of endocrine disorders and belongs to anovulatory functional uterine bleeding. It is recommended to carry out timely examination, ultrasound examination to understand the condition of the uterine adnexa and the condition of the endometrium; the presence of polycystic ovaries can also be carried out to check the hormone level; routine blood tests to understand whether there is anemia. For this case, artificial cycle treatment can be given, usually can be given Yosmin once a day, once a tablet, take 21 consecutive days. Withdrawal bleeding will occur 3-7 days after stopping the drug, and can be taken for 3 consecutive cycles. Usually after the menstrual cycle regulation, menstruation can return to normal. Young girls 15 years old can be given observation after their menstrual cycles are normalized and there is no abnormal uterine bleeding.