Objective: To the effect of external counterpulsation on arterial shear stress in acute ischemia dpgs. Methods: Blood flows were measured at the arteria carotics, truncus brachiocephalics, thoracic aorta and desending aorta for chest-open dogs on the condition of pre-ischemia, one hour after ischemia, two hour after ischemia, one hour after EECP and two hours after EECP, shear stress were operated. The statistic results show that myocardial ischemia make phasic characteristics of shear stress fallen and EECP phasic characteristics of shear stress increased.