Thyroid ultrasound can be used to assist in the diagnosis of thyroid disease, to help identify benign and malignant, to assess the size of the lesion and to follow up after surgery. 1. Identification of benign and malignant: usually, thyroid ultrasound shows irregular nodules, unsmooth edges, hypoechoic nodules, calcified nodules, suggesting that the possibility of malignant nodules is high. If the edges are smooth and the nodules are regular, the possibility of benign is high. 2. Evaluation of lesion size: thyroid ultrasound can evaluate the size of the lesion, whether it is solitary or multiple, the specific location and the surrounding tissues, which is of great significance for preoperative evaluation. 3. Postoperative follow-up: For postoperative patients, thyroid ultrasound should be performed regularly to review the prognosis. Thyroid ultrasound is of high clinical value, but it needs to be combined with the patient’s medical history, symptoms and other examination results to make a correct clinical diagnosis.