Purpose: To investigate the impact of dapagliflozin treatment on blood glucose control, cardiac function, and myocardial injury markers in patients with type 2 diabetes and heart failure. Methods: In a retrospective analysis of clinical data for 132 patients with type 2 diabetes and heart failure admitted to Beijing Tongren Hospital, China from January 2020 to June 2021, these patients were stratified into two groups (66 patients each). Control group received conventional pharmacotherapy and study group received additional treatment with dapagliflozin. Both treatment courses lasted for 6 months. The levels of blood glucose control, cardiac function, and myocardial injury markers before and after 6 months of treatment were compared between the two groups, as well as safety during treatment. Results: After 6 months of treatment, both groups exhibited significant reductions in fasting plasma glucose (FPG), 2-h postprandial glucose (2 h PG), glycated hemoglobin (HbA1c), N-terminal pro-brain natriuretic peptide (NT-proBNP), cardiac troponin I (cTnI), creatine kinase-MB isoenzyme activity (CKMB), aspartate aminotransferase (AST) levels, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), and Minnesota Living with Heart Failure Questionnaire (MLHFQ) score, with study group showing a greater improvement (p < 0.05). Conclusion: Dapagliflozin enhances blood glucose control and cardiac function, improving quality of life in patients with type 2 diabetes and heart failure. Furthermore, Dapagliflozin demonstrates a safe and well-tolerated profile. Future studies will require establishing the mechanism of dapagliflozin action in a larger and more diverse population.