Objective:To investigate the protective effects of Valsartan(Val) on cardiomyocytes injured by hydrogen dioxide(H2O2)in neonatal SD rat. Methods:The protective effects of various concentration of Val on the model of cultured cardiomyocytes injured by H2O2 in vitro were evaluated by detecting the cell viability. The activity of lactate dehydrogenase(LDH),malondialdehyde(MDA),superoxide dismutase(SOD) were also assayed. Results:Val could protect the myocardial cells from H2O2 injury in a dose-dependent manner(2~10 μmol/L), and Val(10 μmol/L) preconditioning showed the greatest protective effect. Val preconditioning could significantly attenuate the increased LDH 1eve1 and antagonize the elevated MDA level and the reduced SOD activity(P < 0.05). Conclusion:Val might be has the protective effects on cardiomyocytes injured by H2O2 through improving cell antioxidant ablility.