Aim To investigate the relationship between carotid artery perivascular fat density and carotid artery stenosis, prognosis. Methods A total of 209 consecutive patients with extracranial internal carotid artery stenosis in Taizhou Central Hospital (Taizhou University Affiliated Hospital) were retrospectively included from January 2017 to January 2021. The carotid artery perivascular fat density in the narrowest axial layer and in the same contralateral axial layer was evaluated by computed tomography angiography. Clinical data of patients were collected. The stenosis was graded according to the guidelines. Symptomatic carotid stenosis was determined according to the medical history. The patients were followed up for one year. Results Carotid artery perivascular fat density was 4.2% higher on the stenosis side than those on the opposite side (P＜0.001). The fat density increased with the stenosis severity. On the stenosis side, carotid artery perivascular fat density was 6.25% higher in symptomatic patients than that in asymptomatic patients (P＝0.015). In asymptomatic patients, perivascular fat density in patients with stenosis related cerebrovascular events occurred within 1 year was 12.4% higher than that in patients without related cerebrovascular events (P＝0.017), and the difference remained after adjusting the clinical parameters by Logistic regression analysis (OR＝1.060,95%CI:1.006～1.117,P＝0.028). Conclusions Carotid artery perivascular fat density is positively correlated with the degree of carotid stenosis. Patients with symptomatic carotid artery stenosis or recurrent related ischemic cerebrovascular outcome events have higher carotid artery perivascular fat density.