Thyroid cancer is a malignant tumor of the thyroid gland, which is a more serious disease, but most thyroid cancers have a relatively good prognosis after active treatment. Thyroid cancer is the most common malignant tumor of the thyroid gland, with certain invasiveness, medullary carcinoma and undifferentiated type as well as advanced thyroid cancer will affect the survival and endanger the life, which is a more serious disease. However, the overall malignancy of thyroid cancer is low. The most important types of thyroid cancer, papillary and follicular, are less malignant and have better prognosis; medullary carcinoma is moderately malignant, and can have better curative effect after active treatment; only a small portion of undifferentiated carcinoma has a high degree of malignancy and has poor prognosis. It is recommended that patients with thyroid cancer should fully communicate with their specialists to clarify the pathological type, stage and other conditions, and choose appropriate treatment plan for active treatment.