Abstract： Objective To observe Rapamycin drug-eluting stent thrombosis after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). Methods Primary PCI with implantation of rapamycin drug-eluting stent was performed in 521 patients with STEMI. Among them, 12 cases suffering from stent thrombosis after PCI were observed. Results The incidence of stent thrombosis was 2.5% ( 13/521), the death rate of the 12 cases in 6 months was 41.7% (5/12). Meanwhile enlarged left ventricular end diastolic diameter and reduced left ventricular ejection fraction occurred in 7 survival patients within 6 months.Conclusion Rapamycin drug-eluting stent thrombosis was a clinical incident with multiple risk factors and related to high mortality and poor prognosis.