Under normal circumstances, the child in 9 ~ 10 years old appeared breast nucleus, so 8-year-old girl long breast nucleus belongs to the normal range of early. The development of breast nucleus, by their own hormone secretion level, environmental estrogen level and nutritional status and other aspects of the impact, such as children after the age of 8 years of breast nucleus, and gradually appeared breast development, ovary enlargement, uterus enlargement, and then appeared pubic hair, the first menstruation, more than that is considered basically normal, such as the child appeared before 8 years of age nucleus of the breast, need to be vigilant about the tendency of precocious puberty. With the improvement of living standards, high levels of estrogen in the external environment, excessive intake of fried foods, or the use of estrogen-containing cosmetics, resulting in the child 8 years old breast nucleus, mostly pseudo-precocious puberty, at this time the child, in addition to the development of breast nucleus, there are no other manifestations. If the child’s own hormone level is high, resulting in 8-year-old long breast nucleus, mostly for true precocious puberty. Therefore, when the 8-year-old girl long breast nucleus, it is recommended to timely pediatric consultation, further clarify the cause of the disease, to take targeted treatment.