If breast development occurs in girls as young as 8 years old, it is mostly due to precocious puberty. Precocious puberty in children can lead to early breast development and significantly early bone age, which can eventually lead to short stature and low self-esteem. Therefore, if a child at the age of 8 years old develops breast development, he or she should go to the endocrinology department of a children’s hospital in time to have his or her sex hormone levels and ultrasound of the uterus and ovaries tested, as well as to have his or her bone age tested in time. If the bone age is significantly early, more than 2 weeks early, timely interventions such as the application of Daphylline should be carried out.