The effectiveness of exercise training in people with COPD is well established. However, alternative methods of training such as Tai Chi have not been widely evaluated. This paper describes the study design of a clinical trial which aims to determine if short form Sun-style Tai Chi improves exercise capacity and quality of life in people with COPD. Method: This randomised controlled trial will be conducted with concealed allocation and blinded outcome assessment. Participants will be recruited from Concord Repatriation General Hospital, Sydney. After baseline measurement, participants will be randomised into either a Tai Chi Group or a Control Group. Participants in the Tai Chi Group will undergo supervised training twice weekly for twelve weeks. Participants in the Control Group will undergo usual medical care. Measurements will be taken at baseline (week 0) and after the study period (week 12). The primary outcome measurement is endurance walking capacity assessed by the endurance shuttle walk test. Secondary outcomes include measures related to peak walking capacity, physical performance, balance, muscle strength and quality of life. Details of the physiological responses during Tai Chi will be collected in a small cohort to determine the training intensity of Sun-style Tai Chi. Discussion: If short form Sun-style Tai Chi improves exercise capacity, physical performance and quality of life in people with COPD, this would provide an alternate form of exercise training which does not require exercise equipment thus making effective exercise training more accessible for the large numbers of people with COPD.