There are more reasons for children’s developmental delay, there are thyroid hormone secretion abnormality will affect the intelligence, if nutrition or growth hormone caused by the general does not affect the intelligence. First of all, the causes of developmental delay in children are more likely to be caused by endocrine abnormalities such as thyroid hormone and growth hormone, and may also be related to nutritional status or genetic factors. Thyroid hormone not only plays an important role in the growth and development of early infants and young children, but also affects intelligence when it functions abnormally; in contrast, growth hormone mainly affects physical growth and development, and has little effect on intelligence. Nutritional deficiencies cause growth retardation because of the lack of substances, but also may have more or less on the development of intelligence, and genetic diseases, such as Down syndrome, children with developmental delay accompanied by obvious mental retardation performance. It is recommended that children with growth retardation should consult a doctor in a timely manner, improve the thyroid function, biochemistry and other auxiliary tests to identify the cause, and then choose the appropriate treatment.