Objective To study the pathogenesis and prevention of subacute thrombosis (SAT) in coronary stents after percutaneous coronary intervention. Methods We reviewed 529 patients who underwent percutaneous coronary intervention (PCI) from January 2004 to August 2007. Among them,5 patients represented SAT associated with coronary stents. The clinical data and angiography results and anti-thrombus treatment of these 5 patients were analyzed. Results (1) The incidence of SAT was 0.94% (5/529),and it mostly presented at 2-5 d after PCI. Three patients had definite stent thrombosis,and coronary angiography showed no stent restenosis after active treatment for 6 months. Two patients had probable stent thrombosis. Two patients died,one in hospital and one after discharge,both due to absence of timely intervention therapy. (2) Among 5 SAT cases,3 patients represented ST-elevation myocardial infarction,1 represented acute left heart failure and cardiogenic shock,1 represented unstable angina. Four patients represented SAT associated with use of drug-eluting stent,and 1 represented SAT associated with use of bare stents. Conclusion SAT may be related to intraoperative stent malposition,acute myocardial infarction,diabetes and C-type diseases. Timely intervention therapy can reduce the hazard for SAT.