Objective To evaluate the image features of isolated superior mesenteric artery lesion (ISMAL) by using 256 slice CT. Methods The images and clinical data of 12 patients were analyzed retrospectively. Every case was analyzed by the methods of vascular reconstruction, such as plain scan transverse axial, enhanced scan transverse axis, the volume rendering (VR), curved planar reformation (CPR), maximum intensity projection (MIP), and summarize the imaging characterization. Results The average age of ISMAL patients was (50.1±2.7)years old, 9 male (75%), 3 female (25%), the prevalence's of SMAD are higher among men than women. 8 patients were superior mesenteric artery embolism (SAME) including5 male and 3 female. 4 patients were superior mesenteric artery dissection (SMAD), all of them were male. The appearance of SMAE were filling defect in arteries and luminal local broadening. The typical manifestation of SMAD was the double chamber display of the strip and low density shadow in the cavity. Conclusion Superior mesenteric artery diseases could be clearly displayed and diagnosed 256 CT plain scan and CTA post-processing technique, and the involvement extent could be confirmed, which provide strong imaging basis for the clinic.