A series of novel conjugates of danshensu (DSS) and tetramethylpyrazine (TMP) were designed and synthesized. Their stability toward hydrolysis by carboxylesterase and cardioprotective effect against t-BHP- and doxorubicin-induced damage were evaluated in H9c2 cells. The results revealed that increasing steric hindrance with bulky groups at the linkage position between DSS and TMP prolonged the half-life and also markedly increased the protective effect. Compound 7 was the most potent in protecting against t-BHP- and doxorubicin-induced damage. The protective effect of compound 7 may in part be attributed to its promotion of mitochondrial biogenesis.