Objective To explore the early predictive value of lymphocyte subsets for cognitive impairment in cerebral ischemia-reperfusion injury.Methods A study was conducted on 68 patients with cerebral ischemia admitted to Honghe Hospital affiliated to Kunming Medical University from January 2023 to December 2023,divided into observation group(n=30)and control group(n=38).The general situation,lymphocyte subsets detection results and Montreal Cognitive Assessment Scale(MoCA)score were compared.Their correlation,sensitivity,specificity were analyzed.Results The proportion of patients with diabetes and levels of CD3+,CD8+and MoCA score in the observation group were lower than those in the control group(P＜0.05),the levels of CD4+,CD4+/CD8+,NK and CD19+in the observation group were higher than those in the control group(P＜0.05);CD3+and CD8+were positively correlated with MoCA score(P＜0.05);CD4+,CD4+/CD8+,NK and CD19+were negatively correlated with MoCA score(P＜0.05).The sensitivity and specificity of lymphocyte subsets combined detection for the diagnosis of cognitive dysfunction in cerebral ischemia-reperfusion injury were 93.45％and 100.00％,respectively.Conclusion The lymphocyte subsets have good predictive value for the occurrence of cognitive dysfunction in cerebral ischemia-reperfusion injury.It can be used as a specific marker.