Abstract： Objective To approach the changes of advanced glycosylated end products (AGEs),surfactant proteins A (SP-A) in the lung of experimental diabetic rats and their relationship. Methods 48 male SD rats were divided into diabetes mellitus (DM) group and control group, each group with 24 rats.The DM rat model was made by injecting streptozocin (60mg/kg) into caudal vein. The rats were killed and the lung was individually taken out at the end of 4, 12 and 20 weeks after the models were established. The changes of AGEs, SP-A in rats lung were observed with immunohistochemical assay and the images were analyzed( black is minimum of gray, white is maximum of gray ). Results We observed a great quantity of AGEs positive cells in the alveolar epithelial cells, bronchial mucosal epithelium, angio-endothelial cell and smooth muscle cells of the DM rats. The average gray (AG) was inferior to that of the controls(4weeks 93.92 ± 7.92 vs 104. 75 ± 8. 20; 12 weeks 76. 25 ± 6. 76 vs 93.50 ± 7.56; 20 weeks 47.63 ± 7.96 vs 142. 38 ± 19. 76; P ＜0. 05) and decreased with the DM course. In the 4 weeks DM rats, there were a few SP-A positive cells in the type Ⅱ alveolar epithelial cells, Clara cells and alveolar macrophage cells. In the 12 and 20 weeks DM rats, there were a great many CTGF and TGF-β1 positive cells. The AG was inferior to that of the controls( 12 weeks 75.63 ± 6. 70 vs 110. 50 ± 13.20;20 weeks 47.38 ± 4. 84 vs 97. 25 ± 9. 87; P ＜ 0. 01 ). Conclusion With the progress of diabetes, DM rats' pulmonary alveolar type Ⅱ cells injury appeared, that might be related with the deposition of AGEs.