Objective：To observe the intestinal tissue injury，epithelial cell apoptosis and changes of glucose regulated protein 78 kD （GRP78） expression in the intestine ischemia-reperfusion rats and to investigate the possible effect and mechanism of endoplasmic reticulum stress in the ischemic process. Methods：Forty-five SD rats were randomly divided into 9 groups：sham control group and 0，1，3，6，12，24，48，72 h groups after ischemia reperfusion（n=5）. An experimental model of intestinal ischemia-reperfusion in rats was established by the occlusion of superior mesenteric artery for 1 h by small atraumatic clip and sham control animals were prepared in the same way without the occlusion of superior mesenteric artery. Intestinal tissue injury severity was tested by HE assay，apoptosis of epithelial cells was measured by TUNEL method and expression of GRP78 in intestinal tissue was detected by Western blot and RT-PCR. Results：HE assay and TUNEL showed that the tissue injury and apoptotic index of intestinal mucosa were gradually elevated with the increasing of reperfusion time and reached a peak at 3 h（P<0.01 compared with those in the other groups）. Expression of GRP78 was increased after the reperfusion，reached a first small peak at 1 h（P<0.05 compared with those in 0 h and 3 h groups），but dropped down with the prolonging of reperfusion time，rose again at 12 h（P<0.004 compared with those in 6 h group），reached the peak again at 24 h（P<0.05 compared with those in the other groups） and fell to the level of control group（P>0.069 compared with those in control group）. Conclusion：Changes of GRP78 expression might be associated with the endogenous protective mechanisms.