Thyroid blood flow signal is the description of blood flow in the thyroid gland during ultrasound examination, and it is related to thyroid nodules, thyroid tumors and thyroid cancer. 1. Thyroid nodule: During color Doppler ultrasonography, it can be found that there is much blood flow signal in the periphery, and the interior is often homogeneous echogenic, with intact peritoneum and clear boundaries, which are usually benign nodules. Typical granulomatous calcified foci with irregular shape and unclear boundary are usually malignant thyroid nodules. 2. Thyroid adenoma: ultrasonography will appear around the nodule signal blood flow surrounding the situation, blood flow is normal, no difference in tissue. 3. Thyroid cancer: ultrasonography indicates that there are many blood flow signals inside the nodule, but the alignment is disorganized, the flow rate is fast, and the blood flow of the surrounding blood vessels is relatively reduced. It is recommended that the patient should consult the hospital to determine the nature of the thyroid blood flow signal, and treat it after making a clear diagnosis.