Objective. To find the effects of dapagliflozin in combination with metoprolol sustained-release tablets on cardiac function and prognosis in acute myocardial infarction patients after PCI. Methods. A total of 84 patients with myocardial infarction who experienced PCI from February 2020 to February 2022 were included and allocated into 3 groups: groups A, B, and C ( n = 28 /per group). Group A was given dapagliflozin combined with metoprolol sustained-release tablets, group B was given dapagliflozin, and group C was given the placebo. Left ventricular end diastolic diameter (EDD), left ventricular ejection fraction (LVEF), and end systolic diameter (ESD) were measured before and after treatment in all groups; myocardial infarction areas were matched among all three groups at 3 months posttreatment. The serum concentrations of interleukin-6 (IL-6), hypersensitive C-reactive protein (hs-CRP), superoxide dismutase (SOD), and malondialdehyde (MDA) were detected in all three groups before and after treatment. The levels of N-terminal probrain natriuretic peptide (NT-pro BNP), lipoprotein (a) (Lp(a)), ischemia-modified albumin (IMA), and secreted frizzled-related protein 5 (SFRP5) were also detected in the serum of all groups. Adverse reactions and cardiovascular adverse events were matched between all groups. Results. The levels of LVEF in groups A and B were increased after treatment, while the levels of EDD and ESD were decreased. The improvement degree of LVEF and EDD levels in groups A and B was found greater compared to group C ( P < 0.05 ). No significant difference was found in myocardial infarction area among the three groups at 3 months postoperation ( P > 0.05 ). Serum concentrations of MDA, hs-CRP, IL-6, IMA, NT-proBNP, and Lp(a) were found to decrease in all three groups after treatment, while the levels of SOD and SFRP5 were increased. The improvement degree of serum hs-CRP, IL-6, SOD, MDA, IMA, NT-proBNP, Lp(a), and SFRP5 levels was greater in both groups A and B compared to group C. The improvement degree of serum hS-CRP, SOD, MDA, IMA, Nt-probNP, Lp(a), and SFRP5 levels was significantly greater in group A compared to group B ( P < 0.05 ). No adverse effect was observed in all three groups ( P > 0.05 ). Total occurrence of cardiovascular adverse effects such as stent thrombosis, heart failure, ventricular fibrillation, and death was 10.71% in group A, 25.00% in group B, and 53.75% in group C. There was statistical significance in the onset of cardiovascular adverse effects 3 months postoperation among all three groups ( P < 0.05 ). Conclusion. Dapagliflozin with metoprolol sustained-release tablets can be effective in improving the heart function, inflammatory response, oxidative stress response, and prognosis in patients after PCI.