Thyroid nodules do not necessarily cause high urinary iodine; they can be caused by either iodine excess or iodine deficiency; the former may cause high urinary iodine, while the latter does not. Thyroid nodules are a common clinical thyroid disease, caused by abnormal proliferation of thyroid cells. The vast majority of iodine within the body is in the thyroid gland, and the iodine ingested by the body is mainly excreted through urine. Both iodine deficiency and excessive iodine intake lead to an increased risk of thyroid nodules. Therefore, for patients with thyroid nodules, who develop the disease themselves with too much iodine in the body, high urinary iodine will occur; for thyroid nodules caused by iodine deficiency, there is no such condition as high urinary iodine. Thyroid nodules can be caused by a wide variety of factors, and individuals who suffer from thyroid nodules are advised to actively cooperate with their physicians according to their actual conditions.