Precocious puberty is a developmental disorder in which girls present secondary sexual characteristics before the age of 8 and boys before the age of 9. Central precocious puberty (CPP) is caused by the hypothalamus increasing the secretion and release of gonadotropin-releasing hormone (GnRH) in advance, which activates the function of gonadal axis in advance, leading to gonadal development and secretion of sex hormones, resulting in the development of internal and external genitalia and the presentation of secondary sexual characteristics. CPP is also called GnRH-dependent precocious puberty, and its process is progressive until the development of the reproductive system is mature. Etiology: 1. Organic lesions of the central nervous system. 2. Peripheral precocious puberty is transformed. 3. Idiopathic CPP (ICPP) without organic lesions. In female children, about 80%-9o% are ICPP; in male children, more than 80% are organic. (1) Early appearance of secondary sexual characteristics: before 8 years old for girls and before 9 years old for boys. (2) Elevated serum gonadotropin levels up to puberty level. (3) Enlarged gonads: ovarian volume >1 ml and multiple follicles >4 mm in diameter seen on ultrasound in girls; testicular volume ≥4 ml in boys, with progressive enlargement over the course of the disease. (4) Accelerated linear growth. (5) Bone age exceeds age by 1 year or more. (6) Elevated serum sex hormone levels to pubertal levels. Among the above diagnostic bases, (1), (2) and (3) are the most important and necessary. However, if the duration of the disease is very short at the time of presentation, the GnRH excitation value may overlap with the prepubertal value and may not reach the above diagnostic cut-off values; the same is true for ovarian size. Such children should be followed for paraphimosis progression and linear growth acceleration and the above tests should be repeated if necessary. In female children, linear growth acceleration during puberty usually occurs about 6 months to 1 year after the onset of breast development (B to B, stage) and lasts for 1 to 2 years; however, there are some late cases, even about 5% of children present one year before or in the year of menarche. In boys, accelerated growth occurs when the testicular volume is about 8 to 10 ml or one year before the change of voice, and lasts longer than in girls. The advancement of bone age only indicates the increase of sex hormone level for a period of time and is not a specific indicator for the diagnosis of CPP. Children with short duration of disease and slow developmental process may not have obvious advancement of bone age, while peripheral precocious puberty may also have advancement of bone age. In summary, the diagnosis of CPP is comprehensive, and the core issue is that it must be consistent with GnRH dependence, and the progressive development of sexual characteristics in clinical follow-up is of great significance. 2.Diagnosis of etiology Attention should be paid to the collection of medical history related to the etiology of CPP, such as infections, central nervous system lesions and other related symptoms; all children diagnosed with CPP should be excluded from tumors, and MRI or CT examination of the cranial saddle area is required. 3.Differential diagnosis Although GnRH excitation test can generally distinguish central precocious puberty from peripheral precocious puberty, it should be distinguished from GnRH excitation test. (1) Pure precocious breast development: In partial central precocious puberty (PICPP), FSH is significantly elevated after GnRH excitation (also elevated in normal prepubertal girls), but LH is not significantly elevated (mostly <5 IU/L) and FSH/LH>1. However, it is noteworthy that PICPP can be converted to CPP in the absence of any clinical aura. Therefore, the diagnosis of PICPP needs to be followed up regularly, especially in cases of recurrent or persistent breast enlargement, with repeat stimulation tests if necessary. (2) In cases of non-central precocious puberty, such as congenital adrenocortical hyperplasia and MeCune?Albright syndrome, the occurrence of CPP must be monitored during the treatment of the primary disease. (3) Congenital hypothyroidism with precocious puberty is a special type of precocious puberty in which the basal LH value is elevated in the early stage of the child, but not after GnRH excitation, and only after a longer course of the disease is the true CPP transformed. short stature is its important feature. The treatment of CPP is aimed at improving the adult height of the child, and attention should be paid to prevent the psychological problems caused by early maturity and early menarche. GnRH analogues (gonadotroping releasing hormone analogue, GnRHa) are generally used for the treatment of CPP, and the slow-release GnRHa preparations currently available for children in China are Triptorelin and Leuprorelin acetate; the former is Decapeptyl Dep and Diphereline; the latter is Enanteline. GnRI-Ia can effectively inhibit the secretion of LH, so that gonadal development is suspended and sex hormone secretion is returned to the prepubertal state, thus delaying the growth and fusion of the epiphysis and achieving the purpose of extending the growth years and improving the final height in adulthood as much as possible. For non-specific CPP, simultaneous etiological treatment should be emphasized (e.g., surgical treatment of saddle area tumors, simultaneous administration of cortisol for congenital adrenocortical hyperplasia combined with CPP, etc.). However, in children with hypothalamic malformation tumors and arachnoid cysts, if there is no elevated cranial pressure, surgery should be deferred and only ICPP should be treated. In conclusion, precocious puberty is a multi-causal abnormality of sexual development, and the identification of the cause is crucial. The identification of GnRH-dependent precocious puberty should exclude central organic pathology, especially in boys and those with onset under 6 years of age (both sexes). GnRHa treatment can be considered as the first choice for idiopathic CPP, but the indications for its application need to be reasonably controlled, and the balance of growth and maturation should be monitored, judged and mastered during treatment in order to achieve improvement of adult height.