Abstract: Objective To observe the findings on coronary computer tomographic angiography（CTA）, coronary arteriography and optical coherence tomography（OCT） in patients with acute coronary syndrome（ACS）. Methods Sixty-four row coronary CTA and OCT were performed to detect lesions in 3 ACS patients before coronary arteriography and after OCT, respectively. The findings on them were analyzed. Resluts Coronary CTA showed soft plaques（which a minimal CT value being less than 100 Hu） complicated by mild calcification in the patients. Positive remodeling was observed in plaques with severe calcification. Plaques with very thin fibrous caps（50μm and 40μm in diameter）accompanying a large lipid pool behind the caps were found on OCT in 2 patients. Conclusion Sixty-four row coronary CTA is rather useful in demonstrating plaques on coronary artery wall, coronary arteriography can dynamically observe changes in coronary artery, and OCT can find plaques, thrombus and fibrous caps.