Abstract： Objective To investigate the differences of clinical features,pulmonary function tests,chest imaging and prognosis between patients with idiopathic pulmonary fibrosis (IPF) combined with emphysema and without emphysema.Methods Of the 117 patients diagnosed as IPF for the first time in the First Affiliated Hospital of China Medical University from January 2002 to January 2007,23 cases met the diagnostic criteria for combined pulmonary fibrosis and emphysema (CPFE).Thirty-three cases with isolated IPF from 2002 to 2003 were selected as the control group.Clinical characteristics,pulmonary function indexes,PaO2,bronchoalveolar lavage fluid (BALF) results and survival time were retrospectively analyzed and compared between the 2 groups.Results The smoking indexes (pack-years) were significantly higher in the CPFE group(28 ± 18)compared with the IPF group (18 ± 16),t =2.10,P ＜ 0.05.No significant difference was observed between the 2 groups in terms of age,gender and the percentage of smokers.The CPFE group showed significantly lower FEV1/FVC％ [(77 ± 7) ％,(83 ± 8) ％,t =3.55,P ＜ O.05] and DLCO％ pred [(44 ± 12)％,(54 ± 16)％,t =2.48,P ＜0.05] compared to those of the IPF group,while TLC％ pred was significantly higher in the CPFE group [(77 ± 11) ％,(64 ± 12) ％,t =3.93,P ＜ 0.05].VC％ pred and PaO2 showed no significant difference between the 2 groups.The total cell count,the percentages of macrophages,neutrophils,lymphocytes and eosinophils in BALF showed no significant difference between the 2 groups.There was no significant difference in median survival time between the 2 groups.Conclusion Smoking was an important risk factor for IPF combined with emphysema.The pulmonary function of IPF combined with emphysema is characterized by a mild abnormality in the lung volume but a significant decrease in the diffusing capacity.Combined emphysema has no influence on the survival time of patients with IPF.