One is hypothyroidism, which is caused by an abnormal and low thyroid function that leads to an insufficient level of thyroid secretion, resulting in a slow thyroid blood flow rate and an abundant thyroid blood flow signal. The other factor is hyperthyroidism, which is caused by an increase in metabolic rate due to hyperthyroidism, resulting in an abundance of blood flow to the thyroid gland on instrumental examination. In short, an abundance of thyroid blood flow is due to abnormalities in thyroid function that cannot be detected by the naked eye and need to be detected by a medical device. An abundant thyroid blood flow signal is not a good sign and should be diagnosed and treated in a timely manner, so as not to ignore it and avoid serious health complications.