Objective To explore the risk factors of osteoporosis and the relation with pulmonary dysfunction in elderly patients with chronic obstructive lung disease (COPD). Methods One hundred and eighty patients (82 females and 98 males) with acute exacerbation of chronic obstructive lung disease (AECOPD) from March 2006 to June 2008 were selected in the study. The bone mineral density (BMD) of lumbar vertebrae and hip joint were determined by dual energy X-ray absorptiometry(DEXA). All the patients were divided into two COPD groups with and without osteoporsis. The smoking history, incidence of vertebral fractures, glucocorticosteroid using condition and so on were recorded. The pulmonary function, 6-minute walk distance(6MWD), body mass index (BMI) and serum albumin concentration were evaluated. Results The mean age of all patients was (72±7)years, and the average smoking amount was (59±27)pack years. The ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) was(36.46±9.8)%, and 30% of the patients had inhaled or oral glucocorticoids for more than 3 months. The BMD measurement results showed that BMD of 95% patients(171 cases) was lower than the normal level, and 119 cases (66%) had osteoporosis, including 61 males and 58 females (62%vs. 70%, x2 = 1.435, P=0.33), and 52 cases had (29%) osteopenia. Linear correlation analysis showed that BMI, 6MWD, RV% and FVC% had positive correlation with osteoporosis (r=0.362, 0.635, 0.688, 0.973;all P<0.05).Conclusions The prevalence of osteoporosis is high in elderly patients with moderate or severe COPD, and enough attention and active intervention shoule be paid.