Objective To dynamically observe the pathological changes and characteristics of the liver injury in spontaneous type 2 diabetic db/ db mice,and to provide a theoretical and experimental basis for studies taking the liver of db/ db mice as a model of type 2 diabetic liver injury. Methods db/ m mice were used as the control group and diabetic db/ db mice were used as the model group (male, 7 - 8 weeks old, SPF grade) with 16 mice in each group. Weight, fasting blood glucose (FBG), serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity were dynamically observed, and the liver index was calculated. Pathological changes in the liver tissues were observed by light and electron microscopies. Results FBG, serum ALT and AST activity in the db/ db mice were significantly higher than those in the db/ m mice. Histological examination revealed that the liver of db/ db mice was damaged severely at 16 weeks of age, including mainly hepatocyte steatosis and infiltration of inflammatory cells. By 32 weeks of age, the disease was intensified and there were massive deposit of collagen fibers in the liver tissue. Electron microscopy showed that mitochondria, endoplasmic reticulum, and other structures were destructed or even absent, and there were significant infiltration of inflammatory cells as well as fat droplets and massive deposit of collagen fibers in liver tissue. Conclusions The liver of db/ db mice can be used as a good liver injury model of type 2 diabetes, displaying obvious steatosis and infiltration of inflammatory cells in 16-week-old mice and obvious fibrosis in 32-week-old mice.