Abstract: Objective To investigate the pathological and magnetic resonance imaging (MRI) characteristics of orbital diffuse large B-cell lymphoma (DLBCL). Methods A total of 48 patients with orbital DLBCL were selected via a retrospective case-control study in the orbital DLBCL group, and 51 patients with DLBCL of primary central nervous system during the same period were included in primary DLBCL group. The clinical characteristics and MRI features of the orbital DLBCL group were analyzed, and the pathological characteristics and peripheral blood platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), and lymphocyte-to-monocyte ratio (LMR) were compared between the two groups. Results The main clinical manifestations of orbital DLBCL patients included local orbital mass in 48 cases (100.00%), limited ocular motility in 38 cases (79.17%), exophthalmos in 33 cases (68.75%), decreased visual acuity in 25 cases (52.08%), diplopia in 17 cases (35.42%), and epistaxis in 9 cases (18.75%). Orbital DLBCL predominantly occurred in the extraconal space (54.17%), with lesions mostly located above the orbit (52.08%). T1-weighted images mainly showed intermediate signal intensity (60.42%), T2-weighted images mainly showed intermediate (56.25%) and high signal intensity (29.17%), diffusion-weighted images mainly showed high signal intensity (58.33%), and apparent diffusion coefficient maps mainly showed low signal intensity (60.42%). There were no statistically significant differences in histopathological subtype, CD20 positive expression, CD79a positive expression, CD45RO positive expression, International Prognostic Index score, and pathological stage between the two groups (P>0.05). The PLR in the orbital DLBCL group was higher, while NLR and LMR were lower than that in the primary DLBCL group (P<0.05). Conclusion Orbital DLBCL exhibits specific clinical manifestations and MRI characteristics. MRI can serve as the primary diagnostic tool, and its combination with pathological immunohistochemical analysis and peripheral blood PLR, NLR, and LMR test results can improve the accuracy and timeliness of diagnosis.