Background: Panax ginseng (Ren shen) has been used to treat chronic obstructive pulmonary disease (COPD). This article aims to present a study protocol and pilot trial comparing P. ginseng with placebo for treating moderate to very severe COPD. Methods: COPD was diagnosed spirometrically, with participants having a forced expiratory volume in one second (FEV1) of between 20% and 79% and FEV1 to forced vital capacity (FVC) ratio of less than 70%. Outcome measures included exacerbation rate, St. Georges Respiratory Questionnaire, COPD Assessment Test and Short-form Health Survey (SF-36). Other outcome measures included the six-minute walk test, FEV1, FVC, relief medication use, use of COPD-specific medical resources, and adverse events. The study is a randomized, double-blind, placebo controlled clinical trial. The method of this pilot trial was based on a planned full-scale trial except that participants were enrolled for ten weeks compared to 52 weeks. In the pilot trial, 14 participants (57-73 years old) with moderate to very severe COPD were recruited from a community health program at a public Chinese medicine hospital in Guangdong Province, China. After a 2-week run-in period, 10 participants were eligible for the study and were randomly assigned to either P. ginseng group (n = 5) (200 mg twice daily for four weeks) or placebo group (n = 5), and then followed-up for an additional 4 weeks for a total of 10 weeks. Results: Nine participants completed the trial and one dropped out. The exacerbation rate could not be evaluated because there were no exacerbations. One participant in P. ginseng group reported events of sore throat, cough and fever. Trial investigators did not consider these events as COPD exacerbations or adverse events. Conclusions: Participant recruitment, study design, data collection and outcome measurement have been tested in a pilot trial. A full-scale trial is warranted.