Abstract: Objective:To investigate the characteristics of diabetes mellitus in the old patients.Methods:The clinical data of 370 old patients with diabetes mellitus were collected and analyzed.Results:Compared with the male patients,the female patients were more easily affected by the peripheral arterial disease and asymptomatic bacteriuria(P0.05).Compared with the patients under the age of 70,the patients over 70 had a higher level of cystatin C and the incidence of asymptomatic bacteriuria,peripheral arterial disease and hypertension increased significantly(P0.05).Conclusions:The old patients with diabetes mellitus often suffer from many basal diseases and chronic complications,so their blood sugar should be controlled properly to avoid hypoglycemia;asymptomatic bacteriuria is one part of the chronic complications.