There are three main factors in the formation of calcified tissues: 1. products after metabolism; 2. traces after infection or speech; 3. tissue changes formed during the development of tumor due to inflammatory reaction; there are many causes of thyroid calcification, although there is a possibility of tumor malignancy, it may also be caused by infections such as Streptococcus hemolyticus, residual calcification of tissues after treatment of simple goiter, etc. Ultrasound manifestation of thyroid calcification is generally divided into microcalcification, coarse calcification, arcuate calcification and circumferential calcification. At present, it is generally believed that microcalcifications have the highest specificity for the diagnosis of thyroid cancer, especially for papillary carcinoma, which can reach 93-95%. In addition, some studies have shown that calcification has a strong correlation with the development of malignancy, especially in young patients and in solitary nodules. Patients younger than 40 years of age have four times the risk of finding a calcified nodule to be malignant than those without calcification.