Calcification of thyroid nodules is a pathologic calcification, which is caused by the accumulation of calcium salts in the cells or interstitial space after damage to the cells or interstitial space due to metabolic disorders that result in the overproduction or overproduction of calcium salts. Calcification in benign thyroid nodules is associated with fibroplasia and cystic degeneration of the nodule, whereas calcification in malignant nodules is associated with hyperplasia of the tissue and secretion of glycoproteins. Thyroid nodules are an imaging manifestation of many thyroid disorders. Thyroid nodules may result from benign conditions such as thyroid cysts and high-functioning adenomas, or from malignant tumors such as thyroid cancer. Calcification of benign nodules may be due to the proliferation of fibrous tissue during the alternating process of hyperplasia and regrowth of the lesion, the blood supply to the thyroid follicular tissue is affected, and ischemia, necrosis, cystic degeneration, and hematoma mechanization within the nodule will be accompanied by calcium salt deposition, resulting in the calcification of the wall of the nodule and the fibrous bundles. Thus benign calcifications tend to be coarse calcifications. Calcification in malignant nodules may be due to the secretion of mucopolysaccharides, glycoproteins and other substances by malignant tumors leading to calcification, or it may be due to the rapid growth of tumors and the fact that tumor tissues are rich in blood vessels and fibrous tissues, which are prone to calcium deposition and the appearance of calcified foci. Therefore, malignant calcification is mostly manifested as tiny calcifications. Calcification of thyroid nodules can be seen in both benign and malignant thyroid diseases. It is recommended that patients consult a specialist to determine the cause of the disease based on the size and shape of the calcified foci and follow the doctor’s instructions for further examination and treatment.