Objective To investigate the relationship between between the levels of serum malondialdehyde(MDA)and superoxide dismutase(SOD),the balance of oxidative/antioxidant stress,and the prognostic nu-tritional index(PNI)and the risk of early neurological deterioration in patients with acute ischemic stroke(AIS).Methods A total of 95 patients with suspected AIS admitted to the Second People's Hospital of Fos-han,Foshan from January to April 2023 were selected as the research subjects.Among them,71 patients who were finally diagnosed with AIS were included in the stroke group,and the remaining 24 non-AIS patients were included in the control group.According to the National Institutes of Health Stroke Rating Scale(NIH-SS)score,the stroke group was divided into the moderate-severe stroke group and the mild stroke group.Ac-cording to whether early neurological deterioration(END)occurred,it was divided into the END group and the non-END group.To analyze the correlations between the levels of serum SOD and MDA,SOD/MDA,and the PNI and the severity of stroke.The receiver operating characteristic(ROC)curve was applied to evaluate the predictive value of each index for the risk of END.By fitting the indicators with high diagnostic efficacy,a Fisher discriminant function model for evaluating the risk of END was established to verify the overall accura-cy rate.Results The levels of serum MDA and SOD,SOD/MDA and the PNI in the moderate to severe stroke group were statistically different from those in the mild stroke group(P＜0.05).There were statistically sig-nificant differences in the levels of serum MDA and SOD,SOD/MDA and the PNI among the END group,the non-END group and the control group(P＜0.05).The areas under the curve(AUC)of SOD,MDA,SOD/MDA and PNI for evaluating END were 0.692,0.727,0.777 and 0.819,respectively.The Fisher discriminant function model established by fitting the NIHSS score,the SOD/MDA and the PNI has an overall accuracy rate of 85.9％.Conclusion The END risk prediction model established by applying the Fisher discriminant function can provide early and objective reference basis for clinical prediction of END risk and has certain practical value.