A thyroid nodule is a mass of abnormal tissue structure within the thyroid gland. The detection rate by neck palpation is 3-7%, while the detection rate by ultrasound is 20-70%. Thyroid nodules are usually found in about half of the people who undergo physical examination. Most of the nodules detected are benign, with malignant nodules accounting for about 5%. There are four common types of nodules: 1) hyperplastic nodular goiter; 2) neoplastic nodules, including benign and malignant tumors; 3) cysts; and 4) inflammatory nodules. The differentiation of benign and malignant nodules becomes the core issue of diagnosis. The corresponding examinations include: 1) high definition ultrasound, nuclear imaging, MRI, CT and other imaging examinations; 2) thyroid function, TPO, TG antibody and other laboratory tests; 3) fine needle aspiration cytology biopsy (FNAC). The nature of many nodules cannot be determined by a single examination, and the nodules themselves are constantly changing, so they need to be reviewed periodically, and the final characterization depends on puncture or surgical pathology.