This study aimed to assess correlations between computed tomography (CT) parameters and pulmonary function test (PFT) parameters in 370 patients with chronic obstructive pulmonary disease (COPD). Patients were classified according to disease severity using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. Emphysema index (EI), air-trapping index, and airway parameters were measured using the automatic segmentation software, Aview, developed by Coreline Soft, Seoul, Korea. The findings indicated that pulmonary function deteriorated as disease severity increased. Parenchymal attenuation parameters worsened in patients with higher GOLD stages, while airway parameters showed a mild correlation with PFT results. For patients with mild COPD, both airway and parenchymal attenuation parameters independently predicted pulmonary function. However, in patients with severe COPD, parenchymal attenuation parameters were the dominant predictors of pulmonary function. These results highlight the potential utility of CT parameters in predicting PFT indices in COPD patients.