Objective To evaluate the effectiveness, safety and feasibility of the application of trans-radial thrombus aspiration in patient with heavy burden of thrombus receiving primary coronary interventional therapy. Methods 56 patients with acute coronary syndrome receiving primary coronary interventional therapy were enrolled and randomized to two groups. 31 patients received therapy of thrombus aspiration by Thrombuster II, while 25 patients received routine coronary interventional therapy. We compared the rate of major adverse cardiac event (MACE) in hospital, left ventricular ejection fraction (LVEF) one week post procedure and left ventricular end diastolic diameter (LVEDD), TIMI frame before and after procedure between two groups. Results The rate of MACE was signiifcantly (P<0.05) lower in patients receiving thrombus aspiration (3.3%) compared with routine PCI group (12.0%). LVEF and the rate of patients with TIMI Ⅲafter procedure were signiifcantly (P < 0.05) higher in patients receiving thrombus aspiration. There’s no significant difference in LVEDD between two groups. Conclusions There lies good safety and feasibility for applying thrombus aspiration combining direct PCI in patient with heavy burden of thrombus.