Objective:To analyze the diagnosis and therapy of primary thyroid malignant lymphoma. Methods:5 cases of primary malignant thyroid lymphoma admitted in the Department of General Surgery in the First Affiliated Hospital of China Medical University between January 2000 and April 2006 were reviewed. Results:Thyroid carcinoma was diagnosed for 5 cases before operation, bilateral thyroidectomy was undergone in 1 case,thyroid and isthmus resection with the involved side and the other side partial thyroidectomy and tracheotomy were done in 2 cases,chemotherapy was undertaken in the above 3 cases after operation.Emergency operation was done because of dyspnoea in 2 cases,postoperative death occurred in 1 case.Postoperative histologic findings were Bcell original NonHodgkin’s thyroid malignant lymphoma in all cases. Conclusion:The right diagnosis is difficult in primary malignant thyroid lymphoma,the patients should be treated with multidisciplinary combined therapy.