Abstract: The prevalence of diabetes mellitus has been increased year by year, and its complications and mortality is a serious health problems in the world. Compared with diabetic retinopathy, the diabetic ocular surface complications were insufficiently studied by ophthalmologists. Keratopathy and tear film changes of diabetes mellitus patients are the main complications with a high incidence. Keratopathy mainly presents as cornea neuropathy and epithelial disease. However, the stardard of diabetic ocular surface lesions is not established yet. Reactive oxidative stress caused by high levels of glucose is key pathogenic factor of keratopathy, so it can provide a research clue for the treatment of ocular surface complications for diabetes mellitus.