Abstract: Objective: To evaluate the correlation between COPD quantitative CT pulmonary function parameters and PFT parameters. Methods: 28 cases of COPD patients, using the maximal inspiratory and maximum expiratory phase spiral CT scanning to analysis the correlation between quantitative CT parameters and pulmonary function test(PFT) parameters. Results: The correlation between COPD quantitative CT pulmonary function parameters of inspiratory phase average lung density, expiratory phase average lung density, inspiratory phase emphysema volume, expiratory phase emphysema volume, inspiratory phase emphysema pixel index, expiratory phase emphysema pixel index and pulmonary function of FEV1/FVC is best(<i<r</i< value respectively 0.44, 0.64, 0.50,0.66, 0.57, 0.64, <i<P</i<〈0.01). The correlation between maximum expiratory phase lung volume and lung function FEV1%(P) is best(<i<r</i< = 0.48, <i<P</i<〈0.01). The correlation between expiratory phase average lung density and lung function PEF(% P) is best(<i<r</i< = 0.40, <i<P</i<〈0.05). The correlation between maximum expiratory phase lung volume, expiratory phase average lung volume density, expiratory phase emphysema and pulmonary function best FEF25% FVC%(P) is best(r value respectively 0.40, 0.44, 0.44, <i<P</i<〈0.05). The correlation between expiratory phase average lung density, expiratory phase emphysema pixel index and pulmonary function MMEF is best(<i<r</i< value respectively-0.57, 0.50, <i<P</i<〈0.01). Conclusion: The quantitative parameters with maximal inspiratory phase and maximum expiratory phase helical CT scanning have a correlation with small airway PFT parameters, and expiratory phase is better than that of inspiratory phase.