If a 5-year-old child develops external genitalia, it suggests that the child is definitely precocious. When precocious puberty occurs, the first thing to do is to go for etiological diagnosis, because precocious puberty is divided into three conditions, true precocious puberty, pseudococious precocious puberty and partial precocious puberty. Only when the cause is clear can targeted treatment be carried out. If a 5-year-old child is pseudoprecocious, if it is caused by the intake of exogenous hormones, the intake of exogenous estrogen should be cut off, such as to eat less food containing animal and plant hormones, and to avoid the child’s intake of contraceptive pills and other factors. If the child has true precocious puberty, it is necessary to see if there are any central pathological conditions, such as whether there are tumors in the pituitary gland of the hypothalamus and whether there are any congenital developmental abnormalities, and if there are, the disposal of these factors should be carried out. If the child has true precocious puberty, he or she should be treated with GnRHa, an analogue of GnRH, which is a GnRH analogue secreted by the hypothalamus, and after treatment, the child’s sexual characteristics will regress significantly and the level of sex hormones will revert completely to prepubertal levels. However, GnRHa injection should be persistent, usually 1 injection every 28 days, until normal pubertal development can be carried out, the treatment time is relatively long, many parents do not understand, think that the treatment can be ended after 1 injection, in fact, this is not the case.