Objective To explore the value of quantitative chest CT in early diagnosis of chronic obstructive pulmonary disease(COPD).Methods The clinical data of 138 cases of COPD high-risk patients in Shanghai community and COPD high-risk respondents in outpatient clinic of Zhongshan Hospital,Fudan University from September 20,2013 to May 20,2014 were retrospectively analyzed.All high-risk participants underwent pulmonary function and chest CT examination at baseline and 1 year later.Chest CT images were imported into quantitative CT analysis software to collect quantitative CT data.These participants were divided into COPD group(n=40)and non-COPD group(n=98)based on their lung functions after 1 year.The differences in baseline lung function and quantitative CT measurements between the two groups were compared.Binary logistic regression was used to analyze the predictors of COPD in high-risk individuals after 1 year of follow-up,and the efficacy of the logistic regression model was evaluated by ROC curve.Results There were no significant differences in gender,body mass index(BMI),the percentage value of forced expiratory volume in 1 second predicted(FEV1%pred),airway wall area ratio(WA%),total airway count(TAC),and airway wall thickness(WT)between the two groups at baseline.Compared to the non-COPD group,the square root of the tracheal wall area at 10 mm from the inner circumference of the airway(Pi10),(3.43[3.30,3.54]vs 3.23[3.15,3.36],P＜0.001),and the percentage area of low attenuation regions below ﹣950 HU(LAA%﹣950),(2.06[0.32,6.29]vs 0.57[0.25,1.89],P=0.015)were significantly higher in the COPD group.The mean lung density(MLD)in the COPD group was lower than that in the non-COPD group([﹣799.89±35.62]vs[﹣783.60±43.52],P=0.038).Binary logistic regression analysis indicated that age and Pi10 were risk factors for COPD(P＜0.05),with an area under the ROC curve of 0.791(95%CI 0.714-0.868).Conclusions In the COPD high-risk population with normal lung function,patients with elevated Pi10 and LAA%﹣950 have a higher incidence of COPD one year later,suggesting that quantitative chest CT measurements such as Pi10 and LAA%﹣950 can assist clinicians in identifying early-stage COPD.