Abstract: Objective To evaluate the efficacy and safety of dapagliflozin tablets combined with insulin aspart 30 injection in the treatment of older adults with type 2 diabetes mellitus (T2DM). Methods A total of 108 patients with T2DM treated at Wuhan No.1 Hospital from September to December 2024 were enrolled and randomly assigned to two groups (n = 54 each) using a random number table. The control group received insulin aspart 30 injection, while the observation group was additionally administered dapagliflozin tablets. The treatment course was 4 weeks, for a total of 3 courses. The therapeutic effects and related indicators were compared between the two groups. Results The total effective rate in the observation group was significantly higher than that in the control group (P ＜ 0.05). After 1 and 3 months of treatment, the levels of fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG), glycated hemoglobin (HbA1c), homeostatic model assessment of insulin resistance (HOMA-IR), and malondialdehyde (MDA) in the observation group were significantly lower than those in the control group, while the homeostatic model assessment of β-cell function (HOMA-β), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were significantly higher (P ＜ 0.05). All these indicators improved significantly from baseline in both groups (P ＜ 0.05). No statistically significant difference was observed in the incidence of adverse reactions between the two groups (P ＞ 0.05). Conclusion The combination of dapagliflozin tablets and insulin aspart 30 injection is more effective in controlling blood glucose, and it can regulate islet function while also alleviating oxidative stress in patients with T2DM, without increasing the risk of adverse reactions.