Objective: To explore the difference of intestinal histological changes induces by ischemia-reperfusion (I/R) between young and adult rats. Methods: 40 SD rats were divided into young and adult groups each 20 with 4 and 10 weeks old respectively. Based on the I/R model of superior mesenteric artery occluded, the intestinal specimens were harvested before and after ischemia 1h, reperfusion 1h and 2h, Chiu’s scores were calculated according to their morphological changes were performed and the data analyzed statistically. Results: There was pathological changes performance for chorionic villi lodging and hyperemia under villi space of intestine after ischemia. Villus necrosis and small ulcer formation, intrinsic layer separation can be found in intestine after reperfusion, there was the aggressive trend with the reperfusion time prolong especially in young group. But for the Chiu’s score, its higher in young group at reperfusion 1h than that in adult group only (P<0.05), no significant difference the scores compared between two groups in another three observe time points ( P>0.05 ). Conclusion: Intestinal tissue damage induced by I/R is severer in young rat than adult and increased with reperfusion prolong.