To enhance the self-management ability of elderly diabetes mellitus (DM) patients, priority should be given to the accurate evaluation of their current self-management ability, and then provide corresponding guidance. To explore the application value of Diabetes Self-Management Behaviors among Older Koreans (DSMB-O) in self-management of elderly patients with type 2 diabetes mellitus (T2DM). Using convenient sampling, this study retrospectively collected the clinical data of 215 elderly patients with T2DM who were admitted to our hospital from June 2020 to June 2022. Enrolled patients were divided into an effective-control group (n= 80) and an ineffective-control group (n= 135) based on whether the glycated hemoglobin (HbA1C) was < 7.5% for further comparison of the collected data. There were statistically significant differences in the comparison of the proportion of diabetes mellitus (DM) course (χ2= 26.000, P< 0.001), DSMB-O score (17.67 ± 4.07 VS 14.67 ± 4.70 points, t= 4.582, P< 0.001), and Summary Diabetes Self Care Activity (SDSCA) score (43.16 ± 11.17 VS 37.58 ± 12.47 points, t= 5.492, P< 0.001) between the two groups. The total score of DSMB-O was negatively correlated with both HbA1c (r=-0.281, P< 0.001) and complications (r=-0.193, P= 0.004); moreover, the total score of SDSCA was also negatively correlated with both HbA1c (r=-0.234, P< 0.001) and complications (r=-0.153, P= 0.025). Among various dimensions of DSMB-O, active exercise (OR= 0.699, 95%CI: 0.541 ∼ 0.902) and blood glucose monitoring (OR= 0.603, 95%CI: 0.431 ∼ 0.817) were protective factors for T2DM patients with HbA1c levels < 7.5%. The area under the curve (AUC) of SDSCA score and DSMB-O score predicting self-management level in elderly T2DM patients was 0.643 (95%CI: 0.611 ∼ 0.756) and 0.716 (95%CI: 0.689∼ 0.774), respectively. DSMB-O exhibits a higher accuracy in predicting the self-management level of elderly patients with T2DM than that of SDSCA. Regular exercise, medication, blood glucose monitoring, and reducing the risk of complications are all intimately associated with the control of blood glucose.