Abstract: Hyperthyroidism in adolescents and children is a common endocrinium disorder, which disturbs the development of diverse body systems, especially of skeletal and central nervous systems. The patients with hyperthyroidism have a lower long-term, spontaneous remission of the disease. The majority of adolescents and children patients with hyperthyroidism have to receive an effective, safe therapy. Currently, there are three methods for treating hyperthyroidism. They include in antithyroid drugs (ATD), surgery and radioactive iodine (¹³¹I) therapy. ATD always is the first line way to these patients with hyperthyroidism for endocrinologist yet. But the remission rate of hyperthyroidism for ATD is lower, the remission of hyperthyroidism also need spend longer time, and side effects of ATD are more common in adolescents and children than in adult. The success ratio and complications of surgery are mainly depended on the technic of surgeons, ¹³¹I has been used as the treatment of hyperthyroidism for more than six decades. So far, there are still no enough evidences to show that the incidence of thyroid cancer and other malignant diseases, the patients' fertility rate, rate of abortion and malformation of descendants in hyperthyroidism patients following ¹³¹I were marked difference with that in other people. The remission rate of hyperthyroidism following ¹³¹I was higher and its side effects were less. ¹³¹I therapy can be the first choice to adolescents and children with hyperthyroidism who are no suitable to ATD therapy. Hypothyroidism is most often one outcome of pediatric patients with hyperthyroidism after ¹³¹I therapy. Hence, the patients with hypothyroidism have to receive the replacement treatment of thyroxine. Since the development of adolescents and children are more dependent on thyroxine and adolescents and children are more sensitive to the radioactive rays than adults, it is more suitable to get ideal control with a relative lower dosage of ¹³¹I to adolescents and children with hyperthyroidism.