In recent years, premature sexual maturity in children has caused widespread concern in society, and the number of infants and young children suffering from premature breast development is also increasing, and society’s concern about premature breast development in infants and young children is not as high as that of older children, one of the reasons is the previous view that simple premature breast development in infants and young children under 2 years of age is a benign self-limiting process, also known as “micro puberty” in infancy and childhood, and can subside on its own without treatment. It is also known as “micro-puberty” in infancy and can subside on its own without treatment. However, recent literature reports have found that this is not always the case, and our department has found through clinical follow-up of children with premature breast development under 2 years of age that some children’s breast enlargement may persist or recur, and eventually progress to central precocious puberty. In addition to nutritional conditions and lifestyle changes, it may also be related to environmental factors. And the 2010 milk powder incident has increased our attention to the effects of environmental factors on the endocrine system, especially the widespread presence of endocrine disruptors (EDCs). Bisphenol A (BPA) and diethyl phthalate (DEP) are considered to be a class of environmental endocrine disruptors with estrogenic activity that can cause changes in endocrine and reproductive functions of the body, and children in the growth and development period are more sensitive to them. Bisphenol A and diethyl phthalate are common plasticizers and are widely used in daily production and daily life. The migration of plasticizers during use has been a concern for scholars, and diethyl phthalate has been listed as a priority pollutant by the U.S. Environmental Protection Agency. Infants and children may be exposed to these two substances through food, mother’s milk, toys, household utensils, etc. Some scholars have studied books for young children and found that they contain BPA, which may be ingested by young children by chewing books so that BPA leaches into their saliva. Foreign scholars have detected BPA in some local cans of commercially available infant formula, and BPA was detected in 2 out of 7 infant formula samples. domestic scholars found that BPA was leached from PC baby bottles, and BPA was detected in the urine of infants using PC bottles, and the concentration of BPA tended to increase with age. There is a lack of research on the correlation between infant breast development and EDCs in China. The group from the Department of Endocrine Genetic Metabolism of Jiangxi Children’s Hospital initially investigated the relationship between EDCs and infant breast development by measuring BPA and diethyl phthalate in the serum of girls with early breast development from 0 to 2 years old and comparing them with normal infants. The results showed that the levels of bisphenol A and diethyl phthalate were higher in the premature breast development group than in the control group, and the urban children were higher than the rural children. It was initially confirmed that endocrine disruptors were associated with early breast development in girls aged 0-2 years, providing a theoretical basis for early intervention in early sexual maturation in infants and young children. Experts suggest that infants and toddlers should not use plastic bottles, contact plastic products and toys as much as possible, mothers should not use skin care products, cosmetics, body washes and shampoos containing hormonal materials, reduce the time babies spend facing computers and TV sets, and have balanced nutrition.