Aim To investigate fungal species distribution and associated susceptibility factors of secondary pul-monary fungal infections in patients with coronary heart disease(CHD)combined with chronic obstructive pulmonary dis-ease(COPD).Methods A total of 68 patients with CHD combined with COPD who developed secondary pulmonary fungal infections were retrospectively selected from those admitted to our hospital from March 2021 to June 2024 as the in-fected group,and the diagnosis was confirmed by pathogenic identification of qualified sputum specimens and alveolar lav-age fluid,while 68 patients with simple CHD combined with COPD were randomly included in the ratio of 1∶1,and were set up as the uninfected group.Clinical data of patients in both groups were collected,Logistic regression model was used to analyze the susceptible factors of secondary pulmonary fungal infection in patients with CHD combined with COPD.The receiver operating characteristic(ROC)curve was used to assess the diagnostic efficacy and accuracy of predictive indica-tors.Results In 68 patients with CHD combined with COPD secondary to pulmonary fungal infections,76 strains of fungi were detected,including 48 strains of Candida albicans(63.16％).Multivariate Logistic regression analysis re-vealed that hospital days(OR=0.160),duration of antibiotic use(OR=0.221),invasive operations(OR=0.248),combined hypoproteinemia(OR=0.104),combined diabetes mellitus(OR=0.269),and combined pulmonary tuberculosis(OR=0.199)were the susceptible factors for secondary pulmonary fungal infection in patients with CHD com-bined with COPD(P＜0.05).The results of the ROC curve showed that the area under the curve(AUC)of hospital days,combined hypoproteinemia,combined diabetes and combined detection for evaluating pulmonary fungal infection in patients with CHD combined with COPD were 0.610(95％CI:0.515～0.705),0.647(95％CI:0.554～0.740,0.603(95％CI:0.508～0.698)and 0.843(95％CI:0.776～0.911),respectively,which were all statistically significant compared with the area covered under the ROC curve of 0.5(P＜0.05).Conclusion The pathogen of secondary pul-monary fungal infection is mainly Candida albicans in patients with CHD combined with COPD.Hospital days,duration of antibiotics,invasive operations,combined hypoproteinemia,combined diabetes mellitus,and combined pulmonary tu-berculosis were risk factors of secondary pulmonary fungal infection in patients with CHD combined with COPD.