【Objective】 To analyze characteristics of the coronary atherosclerotic plaques in patients with acute coronary syndrome (ACS) and stable angina (SA) through the virtual histology-intravascular ultrasound (VH-IVUS), and study the correlation between the coronary atherosclerotic plaques and serum procalcitonin. 【Methods】 Totally 257 patients with coronary heart disease (85 cases in SA group and 172 cases in ACS group) and 120 controls were examined and diagnosed by coronary angiography. The patients with CHD were further examined by intravascular ultrasound, and the gray-scale and virtual histology image data were record. The serum procalcitonin level and hypersensitive C-reactive protein (hs-CRP) level were tested. The correlations between these results and the characteristics of coronary atherosclerotic plaques were analyzed. 【Results】 ① There was no obvious diversity in general information among the three groups. ② The results of VH-IVUS showed that the vascular remodeling index, the proportion of necrotic core and plaque eccentricity index inthe ACS group were statistically higher than those in the SA group (P < 0.05). ③ Serum procalcitonin and hs-CRP levels in the ACS group were significantly higher than those in the SA group and control group (P < 0.05). ④ There were positive correlations between procalcitonin and the proportion of necrotic core, plaque remodeling index and plaque eccentricity index in the ACS group (r = 0.650, 0.622 and 0.629; P = 0.024, 0.016 and 0.023). 【Conclusions】 ① Coronary atherosclerotic plaques in ACS patients are mostly made of necrotic core and partial plaques, while those in SA patients are mostly made of fibrous tissue or fibro-fatty tissue. ② There are obviously positive correlations between procalcitonin and the proportion of necrotic core, plaque remodeling index and plaque eccentricity index in ACS patients.