Radiation iodine is a treatment for hyperthyroidism, which is mainly suitable for hyperthyroidism patients with moderately enlarged thyroid gland, over 25 years old, or allergic to antithyroid drugs, as well as hyperthyroidism patients with relapses after treatment, and if the combination of cardiac, liver and renal diseases and other basic diseases are not suitable for surgery, or hyperthyroidism patients with high-functioning adenomas are suitable for radiation iodine 131 treatment. Stop taking drugs that affect the iodine uptake rate of the thyroid gland and do not eat iodine-containing foods before radioactive iodine treatment. If the symptoms of hyperthyroidism are severe, anti-thyroid medication should be used to control hyperthyroidism first, and radioactive iodine treatment should be performed after the condition has been alleviated in order to prevent the occurrence of thyroid crisis. Then, the dose of iodine 131 treatment is calculated according to the specific condition. Eat after two hours of taking iodine 131, pay attention to rest, prevent infection, exertion and mental stimulation, and do not squeeze the thyroid gland to avoid aggravation of the condition.