Objective To explore the positive rate of emphysema in groups under Low-dose CT screening, then take the regression analysis on related risk factors for emphysema. Methods A total of 1 175 volunteers involved in low-dose CT screening and completing the questionnaire were collected and taken the CT quantitative assessment for emphysema, then the positive rate of emphysema was calculated. Questionnaire data were collected and non-conditional Logistic regression was used to analyze the factors in the questionnaire. Results Ninety-seven cases of emphysema had been detected in 1 175 volunteers, and the positive rate was 8.26%. The positive rate for the males and the females was 9.90% (71/717) and 5.68% (26/458), respectively. Three risk factors (smoking, second-hand smoking, history of chronic bronchitis) were screened out by Logistic regression. Conclusions According to the results of the regression analysis, smoking, second-hand smoking and history of chronic bronchitis are main risk factors for emphysema. Some effective measures could be made against emphysema in high risk population. In that way the morbidity and perniciousness of emphysema could be reduced.