Primary thyroid lymphoma is a rare malignancy of the thyroid， accounting for 1% to 5% of thyroid malignancies and less than 2% of extranodal lymphomas， with an annual incidence of about two in one million. The pathogenesis of PTL has not been fully elucidated， and it is currently believed that it is related to lymphocyte proliferation and malignant transformation caused by chronic inflammatory stimulation. Hashimoto′s thyroiditis is a risk factor for its occurrence. The incidence of different genders is different. Clinically， they often present with a neck mass， or with symptoms of neck compression or obstruction. At present， pathological biopsy is still the gold standard for its diagnosis. Ultrasonography and ultrasound-guided puncture biopsy are commonly used as auxiliary examination means in clinical practice， and play an important role in finding suspected cases and preoperative diagnosis. The treatment and prognosis of this disease are closely related to the pathological classification. Early diagnosis and intervention are of great significance to improve the prognosis. This article reviews the etiology and pathogenesis， clinical pathological features， diagnosis， treatment and prognosis of primary thyroid lymphoma， so as to provide basis and enlightenment for the early diagnosis and the improvement of treatment and prognosis of the disease.