Sexual maturity of nine-year-old girls is a normal phenomenon, no special treatment is needed, considering that the age of puberty development factors related to, can be temporarily observed. If the child’s sexual maturity is caused by disease, such as hypothyroidism, congenital adrenal hyperplasia, tumor, etc., then thyroid preparations, adrenocorticotropic hormone, surgery and adjuvant therapy are needed. 1. Temporary observation: the sexual maturity that occurs before the age of eight can be called precocious puberty, while the phenomenon of sexual maturity of nine-year-old girls, most of the phenomenon is normal, because this age is in the pubertal development, so there is no need for special treatment, and do a good job of care. 2. Thyroid preparations: If the cause of sexual maturity in nine-year-old girls is related to hypothyroidism, you can be diagnosed, with the doctor to give thyroid preparations to regulate, such as levothyroxine. 3. Adrenocorticotropic hormone: some of the nine-year-old girl sexual maturity, consider and congenital adrenal hyperplasia, because after diagnosis with the doctor to give adrenocorticotropic hormone medication, such as hydrocortisone, prednisolone and so on. 4. Surgery and adjuvant treatment: if the cause of sexual maturity of girls is related to tumor factors, they should cooperate with doctors to carry out surgical resection as well as adjuvant treatments such as radiotherapy after diagnosis, so as to improve the symptoms. The use of the above drugs must be applied under the guidance of a professional doctor. It is recommended to consult a doctor in time to clarify the cause of the disease and carry out targeted treatment or therapy with the help of the doctor.