〔Abstract〕 Objective To investigate the effect of nicorandil combined with Wenxin granules for intracoronary injection on the incidence of perioperative major adverse cardiovascular events(MACE) and related prognostic indicators in patients with ST segment elevation myocardial infarction(STEMI) after percutaneous coronary intervention(PCI). Methods 160 STEMI patients were selected as the research subjects, and they were randomly divided into control group, nicorandil group, Wenxin granule group and combination group, with 40 cases in each group. The TIMI blood flow grading, postoperative corrected TIMI blood flow frame number, cardiac function indexes(including 24-hour postoperative cTnI, CK-MB peak value) and the occurrence of perioperative(7 d) MACE events were compared among the four groups of patients condition. Results The incidence of MACE during hospitalization in the control group, nicorandil group, Wenxin granule group and combination group were 47.5%, 30.0%, 30.0% and 22.5%, respectively, and the incidence of postoperative perioperative reperfusion arrhythmia in the combination group was lower in the control group and nicorandil group(P<0.05). The incidence of no-reflow/slow-reflow and the peak value of cTn I in the combination group were lower than thatose in the control group and Wenxin granule group(P<0.05), the peak value of CK-MB was lower than that in the control group(P<0.05), and the cTFC was lower than that in the control group, Wenxin granule group and nicorandil group(P<0.05). Conclusion Intracoronary injection of nicorandil combined with Wenxin granules can reduce perioperative myocardial ischemia injury and effectively reduce the incidence of perioperative reperfusion arrhythmia in STEMI patients after PCI.