The detection rate of thyroid nodules has increased significantly due to the development of diagnostic techniques. According to foreign reports, the incidence of thyroid nodules in the general population is about 30%, of which about one-tenth are malignant, while thyroid cancer has become the most common head and neck surgical malignancy in the United States and accounts for about 1% of all cancers. So, let’s familiarize ourselves with this strange little organ. The thyroid gland is located in the front center of the neck, just below the familiar knot in the throat. Like a butterfly, the thyroid gland has left and right wings (right and left lobes) and a central body (isthmus), and its main role is to secrete thyroxine, which mediates the body’s functions. People with excessive secretion of thyroxine are often referred to as hyperthyroidism, which is characterized by irritability and lethargy, palpitations and hand tremors. If the thyroxine secretion is insufficient, it is hypothyroidism. Therefore, the thyroid gland is like the engine in our body, if it is not functioning well, the consequences are unimaginable. In addition to functional disorders such as hyper- and hypothyroidism, thyroid nodular lesions are also very common in clinical practice. Most thyroid nodules are benign nodules, and a few are malignant nodules, also known as thyroid cancer. If thyroid cancer is treated at an early stage, patients usually have a good outcome. Therefore, it is important to choose the appropriate screening method for early thyroid cancer. High-frequency ultrasound is usually the preferred and effective screening tool. Thyroid cancer lesions in two-dimensional gray-scale ultrasound images, most often shown as blurred boundaries of hypoechoic nodules, some of the nodules have tiny calcification, some nodules aspect ratio is greater than 1, as if standing up oval shape. At a certain stage of disease progression, metastatic cervical lymph node enlargement can also be observed, and in color Doppler ultrasound images, blood flow signals can be observed. In recent years, there are some new ultrasound techniques applied to the diagnosis of malignant thyroid nodules, such as elastography. Simply put, elastography is the use of ultrasound instead of the physician’s hand to palpate the lesions deep in the body, showing the softness or hardness of the lesions through different colors, and generally speaking, malignant lesions are harder. In addition to elastic ultrasound, we can also use ultrasonography to visualize the microvascular pattern of thyroid nodules. For some suspicious nodules, the cellular tissue of the nodule can be obtained by ultrasound-guided fine-needle puncture and observed under the microscope to clarify the benign or malignant nature. Although early thyroid cancer is silent, thyroid nodules can be detected early by regular ultrasound examinations. Nodules suspected to be malignant on routine 2D and color Doppler ultrasound can be further combined with elastic ultrasound, ultrasonography, and ultrasound-guided fine-needle aspiration cytology to identify the benign and malignant nature, and to clarify the need for surgery.