Objective:To investigate the correlation between serum brain-derived neurotrophic factor(BDNF),monocyte to HDL-C ratio(MHR)and post-stroke cognitive impairment(PSCI)in patients with acute ischemic stroke(AIS).Methods:96 patients with acute AIS were collected and divided into PSCI group(n=39,<26 points)and non-PSCI group(n=57,≥26 points)accord-ing to the Montreal Cognitive Assessment(MoCA)score at 3 months after stroke.The clinical data such as serum BDNF and MHR lev-els at admission were statistically compared between the two groups,and the receiver operating characteristic(ROC)curve of BDNF and MHR levels in predicting PSCI was drawn.Results:Compared with the non-PSCI group,the PSCI group was older,had shorter years of education,had a higher proportion of hypertension,and had lower serum BDNF and higher MHR levels,the differences were signifi-cant(P<0.05).Logistic regression analysis showed that age(OR=1.530),hypertension(OR=1.335),serum BDNF level(OR=0.755)and MHR(OR=1.645)were risk factors for PSCI in AIS patients(P<0.05).ROC curve analysis showed that the AUC of BDNF and MHR levels in predicting PSCI were 0.833 and 0.745,respectively,and the AUC of the combined diagnosis of the two was 0.882,which was greater than that of a single index(P<0.05).Conclusion:Serum BDNF and MHR are closely related to PSCI in AIS patients.Both indicators can predict the occurrence of PSCI,and the combined detection of the two can improve the predictive abili-ty.