Objective To investigate the correlation between dual-energy computed tomography (DECT) examination of lung volume and density of chronic obstructive pulmonary disease and lung function in patients with pulmonary emphysema. Methods 102 patients with COPD emphysema from January 2015 to June 2016 were enrolled, and 102 healthy subjects were selected as the control group, all patients received dual-source CT examination and pulmonary function test in 3 days, and the test results were recorded. Results COPD emphysema groups TLC, RV, RV/TLC, Vex, Vin, Vex/Vinwere significantly higher than the control group (P<0.05), FVC, FEV1/FVC, MLDin, MLDex and MLDex-MLDin levels were significantly lower than the control group (P<0.05). Vin-Vex and RV/TLC, FVC showed a negative correlation, positive correlation with FEV1/FVC. MLDex-MLDin and TLC, RV, RV/TLC showed a negative correlation, positive correlation with FVC, FEV1/FVC. Conclusion There is a good correlation between DECT detection of lung volume, density and the pulmonary function index of COPD emphysema patients , with a High clinical value.