Objective To investigate the effects of disease course on cognitive function and related risk factors in elderly patients with type 2 diabetes. Methods A total of 193 patients with type 2 diabetes were selected and divided into 4 groups according to the course of disease, the new diagnosis group, the group of the course of disease within 1 year, the group of the course of disease between 1-5 years and the group of the course of disease over 5 years. The general clinical features, biochemical indicators and neuropsychological test scores among the groups were compared.Results Age (P=0.024), treatment methods (P<0.001), and total cholesterol (P=0.037) were significantly different among the groups of different courses of disease. Logistic regression analysis using cognitive dysfunction as a dependent variable revealed that the course of diabetes (OR=1.205, 95％CI=1.128-1.286) and medical treatment (OR=2.931, 95％CI=1.067-8.053) was associated with cognitive dysfunction. Conclusion There is a cognitive dysfunction in the elderly patients with type 2 diabetes, and the course of diabetes is an important risk factor.