What causes thyroid nodules is not completely clear, the mechanism is more complex, at present, it is usually believed that may be related to iodine deficiency, thyroiditis and other reasons. 1. Iodine deficiency: Iodine is a necessary raw material for the synthesis of thyroid hormones. Long-term insufficient iodine intake will interfere with the normal synthesis of thyroid hormones, causing over-hyperplasia of thyroid cells and the formation of limited nodules. 2. Thyroiditis: Inflammation of the thyroid gland caused by bacterial, viral and autoimmune factors, such as subacute thyroiditis and Hashimoto’s thyroiditis. It is recommended that patients with thyroid nodules go to the hospital in time to improve the ultrasound, fine needle puncture and other tests under the guidance of the doctor, so as to carry out standardized treatment, so as to avoid delaying the condition, leading to adverse consequences.