A thyroid nodule is a nodule that occurs in the thyroid gland, resulting in one or more nodule-like changes within the thyroid gland. There are single and multiple thyroid nodules. Multiple thyroid nodules refer to nodule-like changes in more than two thyroid glands. The cause of multiple thyroid nodules is likely due to a variety of factors, such as genetics, radiation, immunity, infectious factors, iodine deficiency, chemical irritation, and endocrine changes. The first step after the discovery of multiple thyroid nodules is to clarify the diagnosis. Further tests can be performed to check serum T3, T4, TSH and blood thyroid immunoglobulin. Ultrasound of the thyroid gland, fine needle aspiration cytology or tissue biopsy may be performed. Thyroid nuclear scan and PET may also be performed to confirm the diagnosis. The possible causes of multinodular thyroid nodules are nodular goiter, subacute nonsuppurative thyroiditis, benign thyroid adenoma and malignant thyroid cancer. Different treatment methods are used for multiple thyroid nodules of different etiologies. Subacute nonsuppurative thyroiditis can be treated with medications such as adrenal glucocorticoids and thyroid tablets. Nodular goiter can be treated without medication if it is in adolescence or pregnancy and by eating more iodine-rich foods. Young people with simple goiter can take thyroxine tablets. Surgery is required when the goiter becomes compressed, hyperfunctional, or malignant. Thyroid adenoma should be operated early. Thyroid cancer should be treated with surgery plus radiotherapy and endocrine therapy, etc. Thyroid nodules are usually slow-growing and should be treated promptly if they become uncomfortable.