Diffuse enlargement of the thyroid gland is a common thyroid lesion. The danger of diffuse enlargement of the thyroid gland is related to the degree of enlargement of the thyroid gland and the state of hyper- and hypothyroidism, mainly including the following: a. When the enlarged thyroid gland produces compression symptoms, it can compress the trachea and produce symptoms such as chest tightness and breathlessness. Second, if diffuse enlargement of the thyroid gland is combined with hyperthyroidism, typical symptoms of hyperthyroidism may appear, and in severe cases, hyperthyroid heart disease and thyroid crisis may be formed, which may endanger the patient’s life. If diffuse enlargement of the thyroid gland is combined with hypothyroidism, there will be swelling of the face and eyelids, weight gain, unresponsiveness and other hypometabolic symptoms. In severe cases, pericardial effusion, inflammatory edema and coma may occur. Therefore, patients with diffuse enlargement of the thyroid gland need to choose the appropriate treatment according to the degree of enlargement of the thyroid gland and the functional status of the thyroid gland.