Objective To study the correlation between the airway dimensions from third to five generation of bronchi, and pulmonary function test(PFT) results in patients with chronic obstructive pulmonary disease(COPD) by using inspiratory and expiratory multisection computed tomography(MSCT). Materials and Methods The study included 19 patients with COPD who underwent both inspiratory and expiratory CT. For each patient, airway luminal areas and wall thickness from the third to fifth generations of RB1 and RB10 were measured. Correlations between these parameters and PFT results were evaluated. Results The correlation coefficients between airway luminal at expiratory CT and PFT results were higher than those for inspiratory CT, and improved as the airway size decreased from the third to the fifth generations. Conclusion Some parameters of airway luminal are significantly correlated with PFT. MSCT can be used to assess the pulmonary function of patients with COPD.