Objective：A predictive value of neutrophil to lymphocyte ratio（NLR）for intracranial and extracranial artery stenosis in patients with acute cerebral infarction was explored to provide a reference for prediction and prevention of intracranial and extracranial artery stenosis in acute cerebral infarction. Methods：In this study，a total of 145 patients were enrolled in the Department of Neurology of the First Affiliated Hospital of Nanjing Medical University. Patients with ntracranial and extracranial artery stenosis were separated into 2 groups. The rate of intracranial and extracranial artery stenosis <50% was 95，and the stenosis rate of >50% was 50. Collection of baseline data and blood test indicators. All data were statistically analyzed by SPSS 19 software. Results：The age，white blood cell count，neutrophil count and NLR level in the patients with acute cerebral infarction were significantly higher than those in the control group，the differences were statistically significant. Lymphocyte count in the stenosis group was lower than that in the control group，the difference was statistically significant（P < 0.05）. Logistic regression showed that NLR（OR=1.492，P < 0.001）accounts for a risk factor for intracranial and extracranial atherosclerotic stenosis in patients with acute cerebral infarction. The ROC curve analysis showed that the area under the curve of leucocyte was 0.658，the AUC of neutrophils was 0.718，the lymphocyte AUC was 0.631，the combined index AUC is 0.725，and the NLR level AUC was 0.739. The best diagnostic value of NLR was 2.23. Conclusion：NLR plays a predictive role in intracranial and extracranial artery stenosis in patients with acute cerebral infarction.