The main reasons why children do not grow hair are as follows: 1, trace element deficiencies, such as zinc, iron, calcium and other trace element deficiencies; 2, vitamin deficiencies, such as vitamin A, vitamin D, folic acid, vitamin B12 and other deficiencies; 3, sleep deprivation; 4, mental and psychological stress; 5, scalp fungal infections; 6, endocrine diseases, such as hypothyroidism, phenylketonuria and so on. Treatment recommendations are as follows: 1, take the child to the hospital to do trace elements, vitamins and other related checks, according to the results of the appropriate supplementation; 2, in daily life to ensure adequate sleep, reduce mental and psychological stress; 3, diet to allow children to eat a rich diet, balanced nutrition, do not picky, do not favoritism; 4, sun exposure, to promote their own vitamin D production.