Objective: To investigate the effects of dapagliflozin on glucose and lipid metabolism and left ventricular function in elderly patients with type 2 diabetes mellitus (T2DM) and heart failure (HF). Methods: Using a random number table, 60 patients with T2DM and HF who were admitted to the hospital from January 2022 to January 2025 were divided into two group, with 30 patients in each group. The control group was given standard anti-heart failure treatment combined with conventional hypoglycemic treatment, while the observation group was treated with dapagliflozin on this basis. The blood glucose fluctuation indicators, left ventricular function indicators, lipid metabolism indicators, and the incidence of adverse reactions were compared between the two groups. Results: After treatment, the observation group exhibited lower levels of fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG), glycated hemoglobin (HbA1c), triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), and higher high-density lipoprotein cholesterol (HDL-C) level compared with the control group (P<0.05). No significant difference was observed in left ventricular early-diastolic peak velocity (E), left atrial volume index (LAVI), left ventricular ejection fraction (LVEF)and overall incidence of adverse reactions between the two groups (P>0.05). Conclusion: Dapagliflozin can effectively improve blood glucose fluctuations and lipid metabolism disorders in elderly patients with T2DM and HF, but the short-term improvement effect on left ventricular function is not significant.