Aim To evaluate the relationship of T cell subsets and intracranial and extracranial atherosclerosis in patients with Cerebral Infarction. Methods Based on the Trial of Org 10172 in Acute Stroke Treatment(TOAST) criteria, 180 patients with cerebral infarction were classified into large artery atherosclerosis stroke group, cardioembolism group, small-artery occlusion group, other type stroke group and cryptogenic stroke group. The cases were also divided into intracranial and extracranial without arteriostenosis group, intracranial arteriostenosis group, extracranial arteriostenosis group and intracranial and extracranial with arteriostenosis group according to CTA of head and neck. All of the arteriostenosis groups were further divided into mild, moderate and severe groups according to the degree of stenosis. Meanwhile, 60 healthy persons were selected as the control group. T cell subsets levels between groups were compared. Results CD4+ T cells of the cases were obviously higher than those in the control group, while CD8+ T cells were significantly lower than those in the control group(P＜0.05). CD4+ T cells for the large artery atherosclerosis stroke and small-artery occlusion were obviously higher than those in the rest three groups, while CD8+ T cells was opposite(P＜0.05). The severity of intracranial and extracranial arteriostenosis was positively correlated with CD4+ T cells and negatively correlated with CD8+ T cells. CD4+ T cells of the groups of no intracranial and extracranial arteriostenosis were lower than those in the rest arteriostenosis groups, while CD8+ T cells was opposite(P＜0.05). There was no statistical significance for the T cell subsets of all the arteriostenosis groups. Conclusion CD4+T cells and CD8+T cells is closely related to the atherosclerosis of cerebral infarction. There is a predictive value to atherosclerosis formation for detection of T cell subsets.