In recent years, the incidence of thyroid cancer has been on the rise, especially among women. Papillary carcinoma is the most common type of thyroid cancer, accounting for more than 80% of adult thyroid cancer. It is low-grade malignant and prone to cervical lymph node metastasis, but has a good prognosis. Follicular adenocarcinoma accounts for about 15% of thyroid cancer. It is moderately malignant, has the tendency to invade blood vessels, and can metastasize to lung, liver, bone and central nervous system through blood transport. It is less likely to metastasize to cervical lymph nodes and has a slightly worse prognosis than papillary carcinoma. 3.Undifferentiated carcinoma accounts for about 1%, mostly seen in the elderly. It develops rapidly and is highly malignant. It can metastasize to cervical lymph nodes in early stage and easily invade surrounding tissues, such as trachea, laryngeal nerve, esophagus, etc. It can also metastasize to distant places such as lung and bone through bloodstream. It is often found to be inoperable, with very low survival rate and poor prognosis. 4.Medullary carcinoma accounts for about 3%. Unlike the other three types of carcinoma, it originates from parafollicular calcitonin-secreting cells and has a family genetic tendency. Because the tumor secretes calcitonin, patients can show typical manifestations such as diarrhea, facial flushing and low blood calcium. The prognosis is not as good as papillary carcinoma, but better than undifferentiated carcinoma. Overall, papillary carcinoma and follicular carcinoma are differentiated carcinomas, which currently account for more than 95% and have a better prognosis. Once metastasis occurs, most of them can be treated with radionuclide 131 iodine.