Aim To investigate the role of GRP78 and Nur77 in myocardial ischemia-reperfusion injury in diabetic rats. Methods Healthy male SD rats were selected and some rats were ligated to the left anterior descending coronary artery to establish a model of cardiac ischemia-reperfusion. Rats were divided into I/R50 group (18 rats, reperfusion for 50 min), I/R120 group (19 rats, reperfusion for 120 min), diabetic group (13 rats), and normal group (14 rats). Echocardiography was performed 2 hours before and 2 days after surgery. The rats were sacrificed 5 h after operation, and the heart samples were collected. The subcellular organelles were separated by differential centrifugation. The expression of GRP-78 and Nur-77 protein in the nucleus and cytoplasm was detected by Western blot. Results The blood glucose of the diabetic group was significantly increased. Ultrasonic results showed that:The LVEF and LVFS were significantly decreased and the LVEDd was significantly increased in the I/R50 group and the I/R120 group (P<0.05);Compared with the I/R50 group, the LVEF and LVFS in the I/R120 group were slightly decreased, but the difference was not significant. Compared with the diabetic group, the levels of GRP78 and Nur77 in the I/R50 group and I/R120 group were significantly increased in the mitochondria (P<0.05). The Nur77 in the I/R50 group and the I/R120 group were lower in the nucleus (P<0.05). The endoplasmic reticulum I/R50 group and I/R120 group GRP78 were all low expression (P<0.05). Conclusion In ischemia-reperfusion of diabetic rats, GRP78 and Nur77 exhibit mitochondria-targeted translocation, which may be involved in cardiomyocyte apoptosis and lead to myocardial ischemia-reperfusion injury.