Objective:To explore the therapeutic effect and safety of thrombus aspiration catheter in young patients with acute ST-segment elevation myocardial infarction (STEMI) during primary percutaneous coronary intervention (PCI) .Methods :According to using thrombus aspiration catheter during emergency PCI or not ,a total of 79 young patients with acute STEMI were divided into aspiration group (n= 37 ,received thrombus aspiration ) and routine treatment group (n=42 ,didn't receive aspiration catheter ) .Coronary TIMI flow ,angina pectoris symptoms ,cardi-ac function and major adverse cardiovascular events (MACE) etc .after PCI were observed and compared between two groups .Results:Compared with routine treatment group after treatment ,there were significant rise in TIMI flow [ (2.33 ± 0.48) grade vs .(3.00 ± 0.00) grade] ,2h ST segment regression >50% rate (45.24% vs .70.27% ) and left ventricular ejection fraction on the first week [ (47.21 ± 9.28)% vs .(52.16 ± 7.87)% ];significant reduc-tion in angina pectoris symptom (50.00% vs .27.03% ) ,and NYHA cardiac function during follow-up [ (1.52 ± 0.71) class vs .(1.22 ± 0.42) class] in aspiration group , P<0.05 or <0.01. There was no significant difference in incidence of MACE between two groups , P>0.05 all .Conclusion:Application of thrombus aspiration catheter could improve coronary blood flow ,reduce symptoms of angina pectoris and improve cardiac function during primary PCI in young patients with acute STEMI ,and it's safe .