Purpose: We aimed to explore the relationship between pharmacokinetic parameters of DCE-MRI and carotid plaque types based on MRI-modified American Heart Association (AHA) classification. Materials and Methods : Totally 66 patients with 128 plaques were available for analysis finally. After plaques classification according to MRI-modified AHA classification, Ktrans (transfer constant ), kep (efflux rate constant), v p (blood plasma fraction) and v e (extracellular extravascular volume fraction) were measured by two independent investigators. Extended Tofts model was used for calculation of pharmacokinetic parameters. Correlations of different parameters with plaque types were evaluated. The ability of these parameters to distinguish stable (type Ⅲ and Ⅶ ) and vulnerable plaques (type Ⅳ-Ⅴand Ⅵ) was assessed. Results: Significant positive correlation between Ktrans and MRI-modified AHA Lesion Type (LT) Ⅲ to Ⅵ was found (ρ=0.507, P<0.001), so was the correlation between kep and LT Ⅲ to Ⅵ (ρ=0.432, P<0.001). There was no correlation between ve or vp and LT Ⅲ to Ⅵ (ρ= -0.016, P=0.860; ρ= 0.034, P=0.700, repectively). Stable and vulnerable plaques could be distinguished by Ktran s (threshold value 0.045 min-1,sensitivity 76.8%,specificity 82.8%) and kep (threshold value 0.579 min-1,sensitivity 77.8%, specificity 72.4%). Conclusions: Ktrans and kep from DCE-MRI can provide quantitative information to in vivo monitor plaque progression from intermediate to advanced phase and differentiate stable plaques from vulnerable ones. These two parameters could potentially be adopted as imaging biomarkers for plaque characterization and risk stratification.