Objective To explore the relationship between the changes of serum C-C chemokine receptor 5(CCR5)and plasminogen activator inhibitor-1(PAI-1)levels in patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD)and the lung function and the severity of the disease.Methods A total of 114 patients with AECOPD admitted in the Department of Emergency from January 2020 to January 2022 in the hospital were selected as AECOPD group,mean while 114 patients with chronic obstructive pul-monary disease(COPD)were selected as control group.The levels of CCR5 and PAI-1 were measured by en-zyme-linked immunosorbent assay(ELISA).The serum CCR5 and PAI-1 levels and pulmonary function indi-cators were compared between AECOPD group and control group,and in patients with different disease de-grees.Pearson correlation was applied to analyze the relationship between the serum CCR5,PAI-1 levels and pulmonary function indicators in AECOPD patients.Spearman correlation was applied to analyze the relation-ship between the serum CCR5,PAI-1 levels and the severity of the disease in AECOPD patients.Results Compared with the control group,the serum levels of CCR5 and PAI-1 in AECOPD group were obviously higher,and the differences were statistically significant(P＜0.05),and the levels of pulmonary function inde-xes:the first second forced expiratory volume(FEV1),the ratio of FEV1 to forced vital capacity(FEV1/FVC),the percentage of FEV1 to expected value(FEV1％pred),and the percentage of maximum mid expira-tory flow(MMEF)to expected value(MMEF％pred)all significantly decreased,and the differences were statistically significant(P＜0.05).With the increase of the severity of the disease,the levels of CCR5 and PAI-1 in serum gradually increased(P＜0.05),and the levels of FEV1,FEV1/FVC,FEV1％pred and MMEF％pred gradually decreased(P＜0.05).Pearson correlation analysis showed that serum CCR5 and PAI-1 levels were obviously negatively correlated with FEV1,FEV1/FVC,FEV1％pred,MMEF％pred(P＜0.05).Spearman correlation analysis showed that the serum levels of CCR5 and PAI-1 in AECOPD patients were obviously positively correlated with the severity of the disease(r1=0.432,r2=0.451,P＜0.05).Conclusion The levels of CCR5 and PAI-1 in serum of AECOPD patients are obviously increased,and the levels of CCR5 and PAI-1 in serum are closely related to the lung function and disease severity of AECOPD patients.