Abstract: Objective: To investigate the CT manifestations of primary intestinal lymphoma (PIL) so as to improve the diagnosis and differential diagnosis. Methods: 21 patients with PIL confirmed pathologically in our hospital from March 2013 to February 2022 were enrolled in this study, their CT phenotypes and features were analyzed. Results: All 21 cases of PIL were non-Hodgkin's lymphoma (NHL), 12 cases were diffuse large B-cell lymphoma (DLBCL), 3 cases were follicular lymphoma, 2 cases were NK/T-cell lymphoma, 2 cases were T-cell lymphoma, mucosa-associated lymphoid tissue lymphoma (MALT) and mantle cell lymphoma (MCL) were identified 1 case each. The lesions were located in the colon in 7 cases, ileum in 5 cases, small intestine mesentery in 4 cases, ileocecum in 2 cases, jejunum in 1 case, rectum in 1 case, and both right hemicolon and ileocecum in 1 case. CT findings showed intestinal wall infiltration in 3 cases, intestinal wall thickening in 3cases, mass in 4 cases, aneurysmal dilation in 7 cases and mesenteric multiple nodules in 4 cases. CT enhancement mostly showed homogeneous mild/moderate enhancement. Among the 21 patients, 2 case was complicated by by intestinal perforation, and 2 cases were complicated by intestinal obstruction. Conclusion: The characteristic imaging features of CT in PIL include multifocal involvement of the intestines, marked mural thickening in a focal or diffuse manner, aneurysmal dilatation of lumen, eccentric intestinal mass of uniform density and mesenteric "sandwich sign". Recognition of these signs is of diagnostic value for primary intestinal lymphoma.