Abstract： Objective To investigate the relationship between serum homocysteine(Hcy),cystatin C(CysC)and D-dimer(D-D)levels and the condition and short-term prognosis of pa-tients with acute ischemic stroke(AIS)after intravenous thrombolysis.Methods A total of 100 AIS patients who received intravenous thrombolytic therapy in Shunyi District Hospital from October 2019 to June 2023 were selected.According to the National Institutes of Health Stroke Scale(NIH-SS)score,the patients were divided into 3 groups:mild defect group(1-4 points,44 cases),moderate defect group(5-15 points,29 cases)and severe defect group(16-42 points,27 ca-ses).According to the volume of cerebral infarction,the patients were divided into 3 groups:small infarction group(<5 cm3,40 cases),moderate infarction group(5～15 cm3,37 cases),and large infarction group(>15 cm3,23 cases).Three months after intravenous thrombolysis,the patients were divided into 2 groups:good prognosis group(≤2 points,75 cases)and poor prog-nosis group(>2 points,25 cases),according to the modified Rankin scale score.Baseline data of patients were collected,and serum Hcy,CysC and D-D levels were detected.The changes of serum Hcy,CysC and D-D levels in AIS patients with different degrees of neurological deficit,cerebral infarction volume and short-term prognosis were compared.Pearson correlation coefficient was used to analyze the correlation between serum Hcy,CysC and D-D levels and AIS condition.Multivariate lo-gistic regression was used to analyze the independent influencing factors of short-term prognosis of AIS.The receiver operating characteristic(ROC)curve was used to evaluate the predictive value of serum Hcy,CysC and D-D levels for short-term prognosis after AIS intravenous thrombolys-is.Results The levels of serum Hcy,CysC and D-D in the mild defect group were the lowest,fol-lowed by the moderate defect group,and the severe defect group was the highest,with statistically significant(P<0.05).The levels of serum Hcy,CysC and D-D in the small infarction group were the lowest,followed by the moderate infarction group,and the large infarction group was the high-est,the difference between the groups was statistically significant(P<0.05).Pearson correlation coefficient analysis showed that serum Hcy,CysC and D-D levels were positively correlated with NHISS score(r=0.424,0.573,0.716,all P<0.001)and cerebral infarction volume(r=0.633,0.479,0.548,all P<0.001).Univariate analysis showed that the levels of serum Hcy,CysC and D-D in the good prognosis group were lower than those in the poor prognosis group(all P<0.05).Multivariate logistic regression analysis showed that Hcy,CysC and D-D(OR=1.093,1.343,1.146)were independent predictors of short-term prognosis of AIS(P<0.05).ROC curve analysis showed that the area under the curve of serum Hcy,CysC,D-D and the combination of the three in predicting the short-term prognosis of AIS was 0.853,0.873,0.792 and 0.946,respec-tively,and the combination of the three had the highest predictive value.Conclusion The levels of serum Hcy,CysC and D-D are positively correlated with the severity of AIS patients,which can be used as predictors of short-term prognosis after intravenous thrombolysis in AIS patients.