Abstract：Objective：To observe the curative effect of the therapy of Shenmai injection combined with western medicine on no- reflow after percutaneous coronary intervention(PCI) in patients with acute myocardial infarction(AMI) and its effect on myocardial injury and oxidative stress. Methods： A total of 82 AMI patients who received PCI were selected as the research objects and divided into the control group and the observation group according to different treatment methods， with 41 cases in each group. The control group was treated with western medicine，and the observation group was additionally treated with tirofiban injection based on the treatment of the control group before PCI and was treated with intravenous infusion of Shenmai injection based on the treatment of the control group after PCI. The incidence of noreflow was compared between the two groups. Before and after PCI，the changes of levels of myocardial enzyme indexes，including cardiac troponin I(cTnI) and creatine kinase-MB(CK-MB)，and oxidative stress indexes，including superoxide dismutase(SOD) and malondialdehyde(MDA)，were compared between the two groups. The incidence of adverse cardiac events was compared between the two groups. Results： After PCI，the incidence of no-reflow was 21.95% in the observation group and was 43.90% in the control group， the difference being significant(P＜0.05). After PCI， the levels of cTnI and CK- MB in the two groups were decreased when compared with those before PCI， and the above two levels in the observation group were lower than those in the control group，differences being significant(P＜0.05). After PCI，the levels of SOD in the two groups were increased when compared with those before PCI，and the levels of MDA were decreased，differences being significant(P＜0.05)；after PCI，the level of SOD in the observation group was higher than that in the control group，and the level of MDA in the observation group was lower，differences being significant(P＜0.05). The incidence of adverse cardiac events was 7.32% in the observation group and was 24.39% in the control group， the difference being significant(P＜0.05). Conclusion：The therapy of Shenmai injection combined with western medicine can effectively reduce the incidence of no-reflow after PCI in AMI patients，reduce the degree of myocardial injury，and effectively regulate the oxidative stress state of patients，with high safety.