Abstract: OBJECTIVE To analyze the relationship between serological indexes and pulmonary function in patients with chronic obstructive pulmonary disease（COPD） combined with pulmonary fungal infection（PFI）. METHODS A total of 98 patients with COPD and PFI who were admitted to the first hospital of Hebei Medical University from Jan. 2017 to Jun. 2019 were enrolled as the PFI group. Fifty patients with COPD and pulmonary bacterial infection（PBI） who were admitted during the same period were enrolled as the bacterial group. Fifty patients only with COPD were enrolled as the non-infection group. The levels of serum albumin（ALB）, white blood cell count（WBC）, C-reactive protein（CRP）, procalcitonin（PCT） and 1,3-β-D glucan, Forced expiratory volume in 1 second（FEV₁）, forced vital capacity（FVC） and FEV₁/FVC in each group were detected. Receiver operating characteristic curves（ROCs） were applied to analyze the diagnostic value of serum 1,3-β-D glucan for PFI in COPD patients. Pearson correlation analysis was applied to analyze the correlation between serological indexes and pulmonary function in patients with COPD and PFI. RESULTS Totally 113 strains of pathogens were isolated from the 98 COPD patients complicated with PFI, among which Candida spp was dominant, accounting for 76.99%. The levels of WBC, CRP and PCT of the PFI group and the bacterial group were significantly higher than those of the non-infection group（P＜0.05）; the FEV₁, FVC and FEV₁/FVC of the PFI group and the bacterial group were significantly lower than those of the non-infection group（P＜0.05）. The 1,3-β-D glucan level of the PFI group was significantly higher than that of the bacterial group and the non-infection group（P＜0.05）. ROC analysis showed that the AUC of the serum 1,3-β-D glucan was 0.897 in diagnosis of PFI of the COPD patients. Correlation analysis indicated that the FEV₁, FVC and FEV₁/FVC of the COPD patients complicated with PFI were negatively correlated with the serum CRP, PCT and 1,3-β-D glucan（P＜0.05）.CONCLUSION Serum 1,3-β-D may have relatively higher diagnostic value for PFI in COPD patients. The combined detection of PCT and CRP can be applied to evaluate pulmonary function in COPD patients.