Objective To investigate the value and usefulness of optimized multislice CT enterography (MSCTE) with orally administered isosmotic mannitol (2. 5%) as negative contrast in demonstrating the small bowel and its abnormality. Methods Forty patients suspected of intestinal tumors were randomly divided into two groups and underwent conventional or optimized MSCTE. The expansion degree of bowel lumen and the thickness of bowel wall were evaluated for the six segments of the small intestine. The other 20 patients suspected of gastrointestinal diseases underwent gastrointestinal CT imaging.The expansion degree of bowel lumen and the wall thickness of bowel wall were statistically analyzed with Chi-Square test and t test. Results The wall thickness of the stomach, ileum and colon were (2. 56 ±0.52) ,(1.41 ±0. 15),(1.46 ±0. 13),(1.91 ±0. 25), (1.97 ±0.26),(2.01 ±0. 19), (2. 04 ±0.24)and (2. 05 ±0. 18)mm. Optimized method was superior to conventional method in the expansion degree of the second and third segments of the small intestine (P ＜ 0. 05) . There was no significant differences between two groups in the expansion degree and depiction of mucosa for the other segments of small intestine (P ＞ 0. 05). The gastrointestinal CT imaging was poor in the depiction of the duodenum and jejunum, but stomach, ileum and colon were fully illustrated. Conclusion Optimized MSCTE was superior to conventional method in demonstrating the small bowel, and gastrointestinal CT imaging can expand diagnostic scope because of good observation of whole gastrointestinal tract.