Inflammation play important roles in the vulnerability of atherosclerotic plaque. Pericoronary fat is associated with coronary heart disease and high-risk plaque, however the value of pericarotid fat density (PFD) remains uncertain. We evaluated the association between PFD on computed tomography angiography (CTA), with the vulnerable composition of carotid plaques. We found that the PFD was independently associated with vulnerability of carotid plaque especially for IPH and TRFC, suggesting that pericarotid fat tissue may play a key role in the occurrence of vulnerable plaques. The identification of local perivascular inflammation may help identify patients who may benefit from targeted therapy.