The incidence of pediatric precocious puberty in children is increasing year by year, but less than 10% of them are really caused by diseases. 90% of children with pediatric precocious puberty are affected by external factors, among which excessive light stimulation should be taken seriously, especially when children sleep at night, if there are no special circumstances, it is best not to turn on the lights, and as much as possible to ensure adequate sleep. In addition, avoid the light stimulation of the computer monitor for a long time to avoid this triggering precocious puberty in children. What kind of tests should be done for premature pubic hair development? A detailed and complete medical history, including the development of sexual characteristics, vaginal bleeding, and the use of endocrine drugs. Measurement of follicle stimulating hormone FSH and LH in blood by radioimmunoassay can help to differentiate between true and false precocious puberty. In cases of somatic precocious puberty, the ovaries may be enlarged and have cystic changes. If adrenocortical disorders are suspected, posterior glandular wall inflation imaging may be performed. The frontal and lateral images of the skull, the size of the butterfly saddle can be observed to exclude tumors, etc. If the pelvic ultrasound shows multiple follicles ≥4mm in the ovary, it is precocious, if a single follicle >9mm in diameter is found, it is more likely to be a cyst, if the ovary is not large but the uterus is >3.5cm in length and endometrial thickening is seen, it is more likely to be exogenous androgenic. CT or MRI If intracranial tumor or adrenal gland disease is suspected, CT or MRI of the head or abdomen should be performed. Other tests can be selected according to the clinical manifestations of the child, such as T3, T4, TSH for suspected hypothyroidism, increased testosterone and estradiol for gonadal tumors, blood 17-hydroxyprogesterone (17-OHP) and urinary 17-ketosteroids (17-OHP) for children with congenital adrenocortical hyperplasia. -ketosteroids (17-KS) were significantly increased.