Thyroid nodules have a high incidence in the population and are generally detected during thyroid ultrasound. It is sometimes clinically difficult to determine their nature, as some small benign nodules are very similar to malignant nodules and the available tests are very limited in their usefulness, so the clinical experience of the doctor is very important. Malignant thyroid nodules have many specific features, such as scattered calcified foci, rich blood flow, single nodules, and aspect ratios greater than one, as shown by ultrasound and, of course, in combination with clinical manifestations. Because malignant nodules are smaller, there are not many early manifestations of thyroid cancer, and early detection is difficult. Therefore, it is important to stay alert to thyroid nodules, as microscopic cancer is still a very common disease.