ABSTRACT Objective To investigate the correlation between semi-quantitative contrast-enhanced ultrasonography in evaluating neovascularization in carotid plaques and circulating blood neutrophil / lymphocyte ratio (NLR). Methods A total of 132 subjects who underwent carotid plaque contrast ultrasonography were selected and grouped according to the classification of neovascularization in the plaque by semi-quantitative contrast-enhanced ultrasound: 60 cases in grades 1~2 (group A) and 44 cases in grade 3 (group B ) and 28 cases of grade 4 (group C). Meanwhile, the number of circulating blood white blood cells (WBC), the number of neutral cells(NE),the number of lymphocytes(LY) and neutrophil/lymphocyte ratio(NLR) were obtained from the three groups. Spearman correlation analysis of the correlation between plaque contrast ultrasound classification and leukocyte subtypes in circulating blood. Logistic regression further analyzed the independent risk factors that affected neovascularization within the plaque. Results The proportion of patients with cerebral infarction in the three groups was the highest in group C, and the difference was statistically significant (P ＜0.05); WBC and NE increased sequentially in groups A, B, and C, while LY decreased in order, and the difference was statistically significant (all P＜0.01); NLR was the smallest in group A and the largest in group C. The angiographic grading of carotid plaque was positively correlated with WBC, NE and NLR in blood circulation (r=0.30，0.59 and 0.77, all P＜0.01), but negatively correlated with LY （r= -0.50，P＜0.01). Logistic regression analysis indicated that NLR was an independent risk factor for neovascularization in the plaque. For every 1.08 increase in blood circulation NLR, the angiographic grading was increased by one level. Conclusion NLR in circulating blood is closely related to neovascularization in the plaque and is an independent risk factor. For every 1.08 increase in NLR, the angiographic grading was increased by one level.