We found that modified Taohong Siwu decoction (MTHSWD) had cardioprotective effects after myocardial ischemia-reperfusion injury. This study was to screen the effective components of MTHSWD that have protective effects on H9c2 cell injury through H₂O₂ injury model. Fifty-three active components were screened by CCK8 assay to detect cell viability. The anti-oxidative stress ability was evaluated by detecting the levels of total superoxide dismutase (SOD) and malondialdehyde (MDA) in cells. The anti-apoptotic effect was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL). Finally, the phosphorylation levels of ERK, AKT, and P38MAPK were detected by WB (Western blot) to study the protective mechanism of effective monomers against H9c2 cell injury. Among the 53 active ingredients of MTHSWD, ginsenoside Rb3, levistilide A, ursolic acid, tanshinone I, danshensu, dihydrotanshinone I, and astragaloside I could significantly increase the viability of H9c2 cells. The results of SOD and MDA showed that ginsenoside Rb3, tanshinone I, danshensu, dihydrotanshinone I, and tanshinone IIA could significantly reduce the content of lipid peroxide in cells. TUNEL results showed that ginsenoside Rb3, tanshinone I, danshensu, dihydrotanshinone I, and tanshinone IIA reduced apoptosis to varying degrees. The tanshinone IIA, ginsenoside Rb3, dihydrotanshinone I, and tanshinone I reduced the phosphorylation levels of P38MAPK and ERK in H9c2 cells induced by H₂O₂, and the phosphorylation level of ERK was also significantly reduced by danshensu. At the same time, tanshinone IIA, ginsenoside Rb3, dihydrotanshinone I, tanshinone I, and danshensu significantly increased AKT phosphorylation level in H9c2 cells. In conclusion, the effective ingredients in MTHSWD provide basic basis and experimental reference for the prevention and treatment of cardiovascular diseases.