Salvianolic acid A (Sal-A), salvianolic acid B (Sal-B) and danshensu (DSS) are the main active monomers of Salvia miltiorrhiza, a plant used in the treatment of myocardial infarction (MI). A mixture design of Sal-A, Sal-B, and DSS was evaluated to determine the optimal proportion of the three monomers for myocardial protection efficacy. Regression models were established based on the experimental data obtained from oxygen-glucose deprivation H9c2 cells. The response variables included cell viability, creatine kinase MB isoenzyme (CK-MB), cardiac troponin I (cTnI) and myoglobin (Myo). The independent variables were the proportions of the three monomers. An optimal proportion of the three monomers was calculated from the obtained models to simultaneously optimize the four responses: 80 % Sal-A, 10 % Sal-B, and 10 % DSS. The calculated solution proportion was verified experimentally. The results showed that there was no significant difference in the inhibition of cTnI and Myo between the mixture with optimal proportion and the treatment drugs, and the inhibition of CK-MB was even better than that the treatment drugs, including the aqueous extract of S. miltiorrhiza and total salvianolic acid. This study shows that a mixture of 80 % Sal-A, 10 % Sal-B, and 10 % DSS can be the most effective in cardioprotection, providing a basis for the study of the active monomers of S. miltiorrhiza in the treatment of MI.