Objective To investigate the changes and diagnostic value of serum hypoxia inducible factor 1 subunit alpha(HIF-1α)and Toll-like receptor 4(TLR4)levels in patients with chronic obstructive pulmonary disease(COPD)complicated with pulmonary Aspergillosis infection.Methods A total of 240 COPD patients who visited Xi'an Qinhuang Hospital(hereinafter referred to as the hospital)from December 2020 to Decem-ber 2023 were selected as the study subjects in the study,and another 218 volunteers who underwent physical examinations at the hospital were selected as the control group.The COPD patients were separated into an in-fected group(124 cases)and an uninfected group(116 cases)based on whether they had pulmonary Aspergil-losis infection.Enzyme-linked immunosorbent assay was applied to detect the levels of HIF-1α and TLR4 in patients.Fully automated biochemical analyzer was applied to detect lactate dehydrogenase(LDH)and albu-min(ALB)levels.Multivariate Logistic regression was applied to analyze the influencing factors of infection in COPD patients.Pearson correlation was applied to analyze the correlation between HIF-1α and TLR4 levels in the infected group.Receiver operating characteristic(ROC)curve was applied to analyze the diagnostic val-ue of HIF-1α and TLR4 levels for the occurrence of infection in COPD patients.Results Compared with the control group,the COPD group showed an increase in HIF-1α and TLR4 levels(P＜0.05).Compared with the uninfected group,the proportion of dyspnea,antibiotics＞3 types,the duration of antibiotic use ≥ 14 days,mechanical ventilation procedures,the longer glucocorticosteroid(GC)use time,and levels of LDH,HIF-1α,TLR4 in the infected group were higher(P＜0.05),while the level of ALB was lower(P＜0.05).The types of antibiotics＞3 types,the duration of antibiotic use ≥ 14 days,the duration of GC use,and elevat-ed levels of LDH,HIF-1α,and TLR4 were independent risk factors for infection in COPD patients(P＜0.05),while elevated level of ALB was an independent protective factor for infection in COPD patients(P＜0.05).The levels of HIF-1α and TLR4 in the infected group were positively correlated(r=0.453,P＜0.001).The area under the curve(AUC)of HIF-1α and TLR4 in diagnosing infection in COPD patients alone was 0.816 and 0.813,and the AUC of their combined diagnosis was 0.930,which was better than their indi-vidual diagnoses(Zcombination-HIF-1α=4.923,Z combination-TLR4=5.192,P＜0.001,P＜0.001).Conclusion The levels of HIF-1α and TLR4 increase in COPD patients,and further increase after infection with pulmonary Aspergil-lus.They are independent risk factors for infection in patients,and the two are positively correlated.The combined di-agnosis of pulmonary aspergillosis has certain value and provides a theoretical basis for clinical diagnosis.