Objective To evaluate the diagnostic value of medical imaging for primary thyroid malignant lymphomathe(PTML). Methods The medical imaging of 45 PTML cases admitted between January 2000 and December 2014 in the First Hospital of China Medical University were ana?lyzed retrospectively. Results In ultrasound imaging,PTML exhibits a hypoechoic mass and enhancement of posterior echoes,the uninvolved thy?roid tissues also exhibit low echoes but they have clear boundaries with extremely low echo areas of PTML.CT imaging of PTML often shows homoge?neous enlargement of the lobes of the thyroid gland and isthmus with densities lower than the adjacent muscles. In contrast?enhanced CT images,le?sions are moderately enhanced,but they are obviously enhanced in the edge or internal area and the degree of enhancement remains lower than that of the adjacent muscle. Calcification is uncommon. A lesion withcold nodulecan be observed in ECT imaging. Conclusion The characteristic im?aging findings are helpful for preoperative diagnosis of PTML.