Abstract: AMP-activated protein kinase (AMPK) serves as a fuel sensor that plays important roles in regulating energy metabolism in cardiomyoctes under both physiological and pathological conditions. AMPK can be activated under such stresses as ischemia or anoxia, which will lead to less ATP, more AMP and increased ratio of AMP to ATP. After activation, AMPK can inhibit ATP utilization, promote ATP production and increase the total amount of ATP in cardiomyocytes. Therefore, AMPK can protect cardiomyocytes by limitedly extending ATP supply time in ischemia. In addition, AMPK can relieve endoplasmic reticulum stress by inhibiting protein synthesis and reduce apoptosis in myocardium.