Objective To investigate the clinical characteristics of patients with upper urinary calculi complicated with type 2 diabetes mellitus and to provide the basis for the choice of treatment methods. Methods Retrospective analysis of 660 patients with upper urinary calculi including 172 cases of type 2 diabetes mellitus (case group) and 488 cases without diabetes mellitus (control group) were made. Clinical manifestations, various examination results and treatment methods were compared. Results There were statistically significant differencesin hospitalization, preoperative anti infection days, prothrombin time (PT), international standardization ratio (INR), maximum diameter of stone, hydronephrosis, urine culture, preoperative platelet count and clinical manifestations before operation (P < 0.05); there were no statistically significant differences in urinary tract symptoms, use of antibacterial drugs, ICU stay, renal insufficiency and concurrent sepsis (P < 0.05). There was statistically significant difference in operative times (P < 0.05); but there were no significant differences in the causes of multiple surgeries (P > 0.05). Conclusions The clinical symptoms of patients with UUC combined with type 2 diabetes are not consistent with the severity of the disease. The incidence of urinary tract infection, impaired renal function and coagulation function are increased. Surgical tolerance decreases, bleeding and other complications are more prone to occur, and the possibility of reoperation increases. However, the stone volume is relatively small, the hydronephrosis is relatively lighter and the incidence of sepsis does not increase.