Iodine is an essential element in the synthesis of thyroid hormones. The normal brain development of children depends on thyroid hormone, and the critical period is in the first three years of life. Iodine deficiency is the most influential and preventable factor that is known to cause brain neurodevelopmental disorders in children. Therefore, research on the relationship between iodine nutrition and thyroid function of pregnant women and brain development of offspring has always been a hot spot in the research and prevention of iodine deficiency disorders. However, there has been no clear conclusion on the influence and extent of thyroid dysfunction such as hidden iodine deficiency in pregnant women (urinary iodine is 100-150 μg/L), subclinical hypothyroidism and hypothyroidism on the brain development of offspring. This article reviews the research in this field, the related research on the effects of iodine deficiency, iodine supplementation and iodine overdose on children's brain development, and introduces the preventive and therapeutic effects of iodine and thyroxine supplementation during pregnancy.