ObjectiveTo investigate the value of MRI in the diagnosis of central nervous system lymphoma (CNSL). MethodsWe retrospectively analyzed the clinical data of 20 cases of primary CNSL (PCNSL) and 13 cases of secondary CNSL (SCNSL) from the Second People's Hospital of Chengdu and Chengdu 363 Hospital from January to December 2013, and analyzed their clinical data and MRI image data. We observed the tumor location, tumor size and signal, and carried out the statistical analysis. ResultsTwenty patients had PCNSL in the brain, including single lesion in 9 (45.0%), and multiple in 11 (55.0%). Among the 48 lesions, there were 23 (47.9%) nodular lesions, 21 (43.8%) crumb lesions, and 4 (8.3%) dot patch lesions; MRI showed slightly low T1 signal and slightly high T2 signal in most lesions, and showed significant even enhancing, and mild to moderate edema around the tumor. SCNSL lesions were mainly meningeal disseminated with 3 cases (23.1%) of single lesions and 10 cases (76.9%) of multiple ones, and there were a total of 30 lesions. MRI manifested that T1 and T2 mainly showed equal signals, and showed an obviously even enhancing status, and mild to moderate edema around the tumor. ConclusionThe central nervous system lymphoma has a certain characteristic MRI image, and MRI images of the primary and secondary central nervous system lymphoma were similar.