Objective To investigate the influences of depression on exercise capacity of patients with chronic obstructive pulmonary disease (COPD) in 6-minute walk test (6MWT).Methods One hundred and twenty COPD patients,whose acute exacerbation was controlled,were enrolled in the study from September 2009 to April 2011.According to Hamilton depression scale (HAMD) scores,48 patients with HAMD scores ＜ 7 were classified as non-depression group (control),60 patients with HAMD scores ≥17 were classified as depression group,patients with 7 ≤ HAMD scores ＜ 17 were classified as uncertain depression and not included in the experiment.Six-minute walk testing was performed in patients.Blood pressure,heart rates,respiratory rates,Borg scores were measured before and after 6MWT; body mass index and lung function were also measured in all patients.Results The distances of walk in the depression group and control group were (259 ±91) and (312 ±71) meters,respectively (P ＜0.05).Heart rates,svstolic blood pressure,respiratory rates and Borg index in depression group after testing were (108± 11)/min,(148.7 ± 15.4) mm Hg(1 mm Hg =0.133 kPa),(23.3 ±3.9) /min and (4.65 ± 1.67),respectively;those for control group were (95 ±9) /min,(141.8±8.9) mm Hg,(20.2 ±3.7) /min and (2.59±1.52),respectively.There were significant differences between two groups (all P ＜ 0.05).Conclusions Depression may affect the exercise capacity of COPD patients,the psychological status of the patients should be under consideration when conventional treatment is taken.