Objective：To investigate the clinical and computed tomography（CT） differential diagnosis of colonic mucinous adenocar－cinoma and colonic lymphoma，and to improve the accuracy of preoperative diagnosis. Methods：A retrospective analysis was per－formed for the clinical and CT imaging data of 57 patients with pathologically confirmed colonic mucinous adenocarcinoma and 18 patients with pathologically confirmed colonic lymphoma. Results：Compared with the lymphoma group，the mucinous adenocarcino－ma group had significantly higher enhancement rate（ΔR1，ΔR2，and ΔR3） and rate of blurry fatty space（P<0.05）. Compared with the mucinous adenocarcinoma group，the lymphoma group had significantly higher plain scan density of the solid portion of the lesion，homogeneity of tumor during plain scan and contrast-enhanced scan，and proportion of patients with lymphadenectasis and intus－susception（P<0.05）. Among the patients with colonic mucinous adenocarcinoma，6 were found to have hepatic metastasis during follow-up，1 had intestinal perforation with abscess，and 1 had psoas major invasion. There were no significant differences between the two groups in age，sex，clinical symptoms，the location of tumor，shape of bowel wall-thickening，CT values in each enhancement phase，mesenteric and peritoneal involvement，and incidence rates of ileus and peritoneal effusion（P>0.05）. Conclusion：The homogeneity of tumor，plain scan density of the solid portion of the lesion，enhancement rate，invasiveness of tumor，hepatic metastasis，and intussusception may help with the differential diagnosis of colonic mucinous adenocarcinoma and colonic lymphoma.