The diagnosis of thyroid cancer can be divided into two major parts (i) Clinical examination: a swelling in the anterior neck area/swelling in the thyroid area found by physical examination, own examination, or others; an enlarged lymph node in the neck and a common site of metastasis of thyroid cancer; distant metastasis considered to originate from the thyroid gland. Generally, 70% of thyroid cancer patients with left lobe can be detected through clinical examination by head and neck specialist, which is an important way to detect early thyroid cancer. (ii) Adjuvant examinations: ①B ultrasound: It is a highly specific, non-invasive, painless and repeatable examination method. High frequency ultrasound can detect a mass of more than 3 mm. If a mass with unclear boundary, incomplete envelope, internal inhomogeneity of the mass, abundant blood flow, fine gravel calcification and papillary structure are found, it indicates thyroid cancer. (ii) CT and MRI: mainly used to understand the relationship between thyroid swelling and surrounding tissues and organs, whether it invades trachea, esophagus and large blood vessels in the neck, and whether there are metastatic lymph nodes in the neck, etc. ③Nucleotide scan: It is used to understand the iodine absorption function of thyroid swelling. Thyroid cancer is usually cold nodules or cool nodules, but benign swelling with calcification, cystic change, hemorrhage and degenerative carcinoma are all manifested as cold nodules, which cannot be distinguished from cancer, and it is no longer recommended as routine examination in oncology specialty hospitals in recent years. However, the puncture is only a limited part of the thyroid swelling and is not 100% accurate, and the impact of the puncture on the future surgery should be taken into consideration (the normal tissues that have to be removed during the surgery will be more traumatic and there is a possibility of needle metastasis). If the puncture has no guiding value in the scope of surgery, puncture is not advocated, and intraoperative freezing can be considered.