Objective To investigate the distribution of pathogens and risk factors of acute exacerbation of chronic obstructive pulmonary disease (COPD) in elderly patients with pulmonary infection. Methods Two hundred and sixty elderly patients with acute exacerbation of chronic obstructive pulmonary disease in our hospital were selected. All patients were divided into infection group and non-infection group accorded to the occurrence of pulmonary infection. The clinical data of all cases were recorded, and the pulmonary infection patients were given analysis of the risk factors and the pathogens distribution. Results There were 30 patients of pulmonary infection in the 260 patients (11.5%). In the infection group, a total of 45 strains of pathogen including 25 strains of gram negative bacteria, 18 strains of gram positive bacteria, 2 strains of candida spp. were isolated. The top 4 pathogens were Pseudomonas aeruginosa, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus etc. The Pseudomonas aeruginosa, Klebsiella pneumoniae had relatively high rate of resistance to erythromycin, gentamicin, and the Pseudomonas aeruginosa, Staphylococcus aureus had relatively high rate of levofloxacin and meropenem. Univariate regression analysis showed that the history of diabetes, smoking, long-term use of antibiotics, long-term use of hormones, long-term bed were significant different in the infection group and in non-infection group (P<0.05); Non conditional Logistic regression analysis showed that the diabetes (OR=10.593, P=0.000), smoking (OR=6.194, P=0.008), long-term use of antibiotics (OR=3.255, P=0.014) were the risk factors of pulmonary infection (P<0.05). Conclusion Pulmonary infection was common in acute exacerbation of chronic obstructive pulmonary disease, Gram-negative bacteria might be the main pathogen. Diabetes, smoking, long-term use of antibiotics were the risk factors of pulmonary infection.