Objective To explore the effect of blood glucose changes on multiple organ dysfunction syndrome in the elderly (MODSE), and to evaluate the value of blood glucose changes in predicting and diagnising MODSE in elderly patients with non diabetic pulmonary infection. Methods A retrospective study was carried out on 429 patients over 65 years old with non diabetic pulmonary infection in Bethune International Paeace Hospital of PLA from January 2005 to December 2014. According to the onset of MODSE induced by pulmonary infection, all patients were divide into MODSE group(n=95) and non MODSE group(n=334). The highest fasting blood glucose levels in MODSE group and non MODSE group were compared. The ROC curve of the highest fasting blood glucose level in elderly patients with non diabetic pulmonary infection was drawn, and the area under the ROC curve was calculated. The predictive accuracy and diagnostic accuracy of different blood glucose levels were assessed using sensitivity and specificity, and the optimal prediction point and diagnosis point for MODSE was found. Results The highest fasting blood glucose level in the MODSE group was significantly higher than that in the non MODSE group[ (8.656?.664) vs (5.679?.332) ，t = 10.523、P ＜0.001]. The area under the ROC curve was 0.880, and 95% CI was 0.835-0.926（P ＜0.001）. When taking the fasting blood glucose 6.875mmol/L, the sensitivity was 82.2%, the specificity was 90.1%. Conclution The blood glucose changes in elderly patients with non diabetic pulmonary infection is valuable in predicting and diagnising MODSE induced by pulmonary infection.