Objective To investigate the prevalence and risk factors of depression in elderly patients with type 2 diabetes mellitus（T2DM） . Methods Totals of 550 elderly T2DM patients in Meilong Community Health Service Center of Shanghai City Hospital from January 2015 to December 2016 were investigated by Patient Health Questionnaire（PHQ-9）. According to PHQ-9 scores， patients were divided into comorbid depression group and non-depression group. Demographic data were compared between two groups. Multivariate Logistic regression analysis was used to explore the risk factors of diabetes combined with depression. Results The incidence of depression in elderly patients with T2DM was 45.27%. The duration of diabetes mellitus， number of somatic diseases， fasting blood glucose and HbA1C were independent risk factors of comorbid depression in community elderly patients with T2DM（ P＜0.05）. Conclusions The incidence of depression is high in elderly diabetes patients. In addition to the positive control of blood glucose and HbA1C， possible symptoms of depression should be actively concerned in the guidance and treatment of community elderly diabetes mellitus patients in order to early prevention， early detection and timely treatment.