Objective:To observe the effects of Shexiang Tongxin Dropping Pill (STDP) on the myocardial reperfusion in patients with acute ST elevation myocardial infarction (STEMI) after percutaneous coronary intervention (PCI). Methods160 patients with STEMI before undergoing PCI were randomly divided into the treatment group and control group, 80 cases in each group. Both groups were treated with routine western medicine before and after PCI. The treatment group was treated with STDP by sublingual administration before coronary arteriography and oral administration after PCI, and the control group was treated with placebo by the same methods, with a course of one month. The intervention indicators during operation were observed, the postoperative myocardial reperfusion indicators and the left ventricular ejection fraction (LVEF) one month after operation were compared.  Results:①Finally, 153 patients including 75 patients in the treatment group and 78 patients in the control group completed the trial. ②There were no statistically significant differences on PCI intraoperative medication (tirofiban and heparin), application of suction catheter, infarction related artery and number of implanted stents between the two groups (P>0.05). ③The ST segment fall rate in the treatment group was significantly higher than that in the control group (P<0.05), while the corrected TIMI frame count (cTFC) in the treatment group was significantly lower than that in the control group (P<0.05). ④Compared with 3 days after operation, the LVEF level was obviously increased in the treatment group one month after operation (P<0.05). One month after operation, the LVEF level in the treatment group was obviously higher than that in the control group (P<0.05).  Conclusion:Shexiang Tongxin Dropping Pill can significantly improve the myocardial reperfusion and enhance the short-term cardiac function in STEMI patients after PCI surgery.