Objective To analyze the value of quantitative computed tomography (CT) combined with pulmonary function parameters in differentiating different types of chronic obstructive pulmonary disease (COPD).Methods A total of 132 COPD patients admitted to our hospital from January 2019 to January 2022 were selected as the research object, including 58 cases of emphysema COPD and 74 cases of bronchitis COPD, and 100 healthy adults were selected as the control group during the same period. Dual-phase CT scans at the end of deep inspiratory and end of deep expiratory were performed on all subjects. Lung volume, pulmonary vascular volume, pulmonary vascular volume, mean lung density, percentage of low attenuation area (< -950 HU) in total lung volume (LAA%_-950) and other indicators were collected, and lung function was examined. The percentage of the actual measured forced expiratory volume of 1s to the predicted value (FEV₁%pred), the percentage of the actual measured forced vital capacity to the predicted value (FVC% pred), the percentage of all expiratory volume of the first second at the two stations of forced expiratory volume (FEV₁/FVC), carbon monoxide dispersion (DLCO) and other indicators were collected. The baseline data, CT quantification and pulmonary function examination results of COPD group and control group were compared. The differences of CT quantification and lung function indexes between patients with emphysema COPD and bronchitis COPD were compared. ROC was used to analyze the value of CT quantitative indexes and lung function indexes in distinguishing emphysema and bronchitis COPD. The value of CT quantification combined with lung function index in distinguishing emphysema and bronchitis COPD was analyzed by consistency analysis. The risk factors of COPD were analyzed by conditional Logistic stepwise regression.Results Compared with the control group, the proportion of patients with smoking history and special occupational exposure history was higher in COPD group, and lung volume, pulmonary vascular volume, FEV₁%pred, FVC%pred, FEV₁/FVC, and DLCO were lower in COPD group (P < 0.05). Compared with patients with bronchitis COPD, pulmonary vessel volume, mean lung density and LAA%_-950 were higher in patients with emphysema COPD (P < 0.05); compared with bronchitis COPD patients, the levels of FEV₁%pred, FVC%pred, FEV₁/FVC and DLCO in emphysema COPD patients were lower (P < 0.05); after ROC analysis, pulmonary vascular volume ≥ 111.175 mL, mean lung density ≥ -841.933 HU, LAA%_-950 ≥ 34.613, FEV₁%pred ≤ 42.787%, FVC%pred ≤ 64.989%, FEV₁/FVC ≤ 54.755%, DLCO ≤ 62.159 mmoL/(min·kPa) was the best cut-off value of emphysema COPD (all P < 0.05); the results of consistency analysis showed that the sensitivity, specificity, and accuracy (κ = 0.831) of quantitative CT combined with lung function in identifying emphysema COPD were 91.38% (53/58), 91.89% (68/74), 91.67% (121/132), respectively. The sensitivity, specificity, accuracy, and Kappa value of quantitative CT combined with lung function in the identification of bronchitis COPD were 91.89% (68/74), 91.38% (53/58), 91.67% (121/132), κ = 0.831. Multivariate Logistic regression analysis showed that smoking history, special occupational exposure history, lung volume, pulmonary vascular volume, FEV₁%pred, FVC%pred, FEV₁/FVC, DLCO, and other factors may be the risk factors for COPD.Conclusion CT quantification and lung function indicators have high value in the discrimination of emphysema COPD and bronchitis COPD alone or in combination. The sensitivity and specificity of the two combined applications in the discrimination of emphysema and bronchitis COPD are higher than that of the single application.