Hyperthyroidism is the abbreviation of hyperthyroidism, iodine 131 treatment of hyperthyroidism has few side effects, the common side effects are mainly hypothyroidism, with an annual incidence of 2%~3%. Iodine 131 releases β-rays during the decay process, and β-rays have strong ionizing radiation ability, which makes part of the thyroid follicular cell degeneration and necrosis, and reduces the synthesis and secretion of thyroid hormones, and the volume of the thyroid gland is also reduced, thus achieving the purpose of treating hyperthyroidism. Iodine 131 radiation therapy is contraindicated in pregnant and lactating women. Patients with hyperthyroidism who need Iodine 131 radiation therapy should actively cooperate with their doctors to avoid delays and serious consequences.