Objective To study the value of CT in diagnosis and identification of mediastinal lymphoma. Methods CT imaging data of 30 patients with mediastinal lymphoma confirmed by pathology were retrospectively analyzed. The CT findings such as the location, size, shape and density of the mediastinal lymphoma were observed and compared with pathological findings. Results Compared with the pathological findings, the accurate rate of CT in diagnosis of mediastinal lymphoma was 90.0% (27/30). Another 3 cases were misdiagnosed as mediastinal thymoma. All were lymphadenectasis and mainly were multiple lymphadenectasis; All swelling lymph nodes fusion accounted for 26.7%, showing lobulated or wavy irregular soft tissue masses. CT plain scan mainly showed homogeneous density and enhancement scan mainly was homogeneous enhancement, accounting for 90.0%. 21 cases (70.0%) were with vascular displacement. There were anterior segment of bone destruction of sternum and rib, chest wall soft tissue masses and pericardial effusion and pleural effusion in respctively 8 cases. Conclusion The accurate rate of multi-slice spiral CT in the diagnosis of mediastinal lymphoma is high. It can be used as an important method for diagnosis and identification of mediastinal lymphoma.