Undifferentiated carcinoma of the thyroid is rare and includes mainly large cell carcinoma, small cell carcinoma and other types of carcinoma (squamous cell carcinoma, giant cell carcinoma, adenoid cystic carcinoma, mucinous adenocarcinoma, and poorly differentiated papillary and follicular carcinoma). The etiology of this disease is unknown, and the incidence is higher in areas with endemic goiter. In 2002, the Joint Committee on Cancer Research of the United States classified undifferentiated thyroid cancer as stage IV in TNM staging, regardless of the size of the primary site or lymph node metastasis. Undifferentiated carcinoma is one of the most aggressive malignant lesions that is difficult to control and there is still a lack of satisfactory treatment. Surgical resection should be the preferred treatment for all thyroid cancers, including undifferentiated carcinoma, when available, because the efficacy of surgical treatment is certain and it lays the foundation for future non-surgical treatment. There are various surgical methods, but they are not the only treatment methods. Non-surgical treatment is an option when there is no surgical condition, or for adjuvant treatment after surgery. Although undifferentiated thyroid cancer occurs in follicular cells of the thyroid gland, endocrine therapy is generally not used because of its poor differentiation and poor dependence on the pituitary thyroid axis system. However, the administration of thyroxine is also necessary, especially for patients after total thyroidectomy, mainly for its compensatory effect and to relieve or mitigate the side effects associated with hypothyroidism. There is a growing consensus on the status of multimodal comprehensive treatment in the treatment of undifferentiated thyroid cancer, and surgical resection is one of the important means. For those who can be resected surgically, surgery is preferred, but over-expansion causing important dysfunction must be avoided. For those with clinical lymph node metastasis, neck clearance must be performed at the same time. Postoperative combination of radiotherapy can help to improve local control and survival rate. If there is no distant metastasis after radiotherapy and the local tumor can be resected, surgery should be performed if serious complications can be avoided. In addition, anti-angiogenic drugs have been used as the mainstay of the treatment. In addition, the new targeted therapy represented by anti-angiogenesis provides new methods and new ideas for the treatment of undifferentiated thyroid cancer, but it is still in the experimental stage and needs further research and clinical validation.