Abstract: Objective: To assess the clinical significance of coronary flow velocity assessing by the method of frame counting in reperfusion therapy of acute myocardial infarction（AMI). Methods: In 90 patients with AMI, after being taken successfully direct or rescue percutaneous transluminal coronary angioplasty（PTCA), the frame counting method was used to count the number of cineframes of infarction related artery（IRA). The flow velocity of IRA was detected by the combination of the length of IRA and the cardiac function was measured by echocardiogram after PTCA. Results: In all the patients, the mean number of cineframes of IRA was 37.36 19.70, and the flow velocity of IRA is 134.58 47.57mm/s. The flow velocity of IRA was positive relation with the left ventricular ejection fractions （r=0 74, P =0.00) and CTFC was negative relation with the left ventricular ejection fractions （r=-0 64, P=0.01).The patients with CTFC ＜30 had higher LVEF and lower incidence of cardiac events （P ＜0.05, respectively).The flow velocity of IRA were significantly different between the group with cardiac events and the group without cardiac events（167.20±36.75 vs 105.78±30.85, P＜0.05). Logistic regression showed the flow velocity of IRA was well related with the incidence of cardiac events during admission（OR =2.41,95%CI=1.95～2.83, P=0.00). Conclusions: The frame counting of IRA is a simple, objective and quantitative method that allows standardization of the IRA flow, and associated with cardiac function and the incidence of cardiac events during admission.