Objective: To detect the expression and distribution of I-FABP in intestinal tissue and the changes of serum concentrations at different time of acute intestinal ischemia, and explore the significance and mechanism of I-FABP in early diagnosis of acute ischemic bowel disease. Methods: The selected 96 healthy adult SD rats were randomly divided into the experimental group and control group; 48 in each group. Each group was randomly subdivided into 6 groups with 8 rats in each group. The superior mesenteric artery was ligated in the experimental group and the peritoneal switch operation was performed in the control group. The venous blood samples were extracted from each group rats’ right ventricle at 0.5 h, 1 h, 2 h, 4 h, 8 h, 12 h after the operation and the concentration of I-FABP was tested respectively. Then the rats were killed, and the diseased intestinal tubes were cut out for paraffin sections. The I-FABP in intestinal tissue was stained by routine HE staining and direct immunofluorescence staining. Results: The I-FABP was mainly expressed in the epithelial villi of intestinal mucosa, and there was a small amount of expression in the intestinal submucosa and even the muscularis. Within 1 hour of intestinal ischemia, the number of I-FABP positive granules in the intestine and intestinal cavity increased gradually, and then gradually decreased after 1 hour. The difference has statistically significant between the experimental group and the control group (P < 0.05). The serum I-FABP: In the experimental group, the serum I-FABP concentration began to increase at 0.5 h, and reached a peak at 1 h (290. 24 ± 156.69) μg·L–1, then gradually decreased. Compared with the control group, the difference was statistically significant (P < 0.05). Conclusion: I-FABP usually mainly exists in the epithelial cells of intestinal mucosa. When acute intestinal ischemia occurs, the epithelial cells of intestinal mucosa permeability changes; I-FABP expression rapidly releases to intestinal tissue and intestinal cavity, and is absorbed into the blood. Therefore, I-FABP has certain clinical significance in early diagnosis and treatment of acute intestinal ischemia.