Abstract: Objective: Our study is to investigate the effects of Angiotensin Ⅱ (ANGⅡ) on the myocyte viability and the cellular basis of myocardiocyte dysfunction, in order to provide the evidences for better management of heart failure.Methods: Based on that the mitochondria of viable cells can act on MTT to produce formazan with light purple, we investigate the effect of ANGⅡ on the cultured myocyte viability by means of colorimetric method.Results: Our results showed that ANGⅡ caused the gradual increase of formazan optical density (OD) in 12 hours, and the formazan OD reached the peak at 12 hour, thereafter decreased, even lower than the normal at 24 hour. CV11974 did successfully and significantly antagornized the effect of AngⅡ on the cardiac myocyte viability (P <0 05 or 0. 01). Conclusion: Our results indicated that AngⅡ could improve the myocytes viability at the early stage. It has important meanings for the correct use of ANGⅡ and the efficient management of heart failure in the future.