Thyroid cancer can be diagnosed by ultrasound, but a definitive diagnosis requires puncture pathology. Because puncture biopsy is the gold standard for thyroid cancer diagnosis. Ultrasound belongs to imaging examination, according to the presence or absence of echoes inside the thyroid nodule, calcification, border clarity and aspect ratio, etc., it can initially diagnose thyroid cancer, but it can’t directly confirm the diagnosis of thyroid cancer. If ultrasound examination shows echogenicity and calcification inside the thyroid nodule, unclear border and disordered aspect ratio, thyroid cancer can be highly suspected. If the pathologic report of puncture biopsy is available, the diagnosis of thyroid cancer can be completely confirmed. If the result of puncture examination is negative, thyroid cancer cannot be completely ruled out yet because the tumor tissue may not be punctured. If the ultrasound examination finds some characteristics of thyroid cancer, it is suspected that the possibility of malignant tumor is higher, it is recommended to cooperate with professional oncologists to improve the puncture biopsy as soon as possible to confirm the diagnosis as soon as possible.