Abstract: Objective To evaluate the effect of three-ball breath training device on pulmonary function for older patients with stable chronic obstructive pulmonary disease (COPD). Methods Sixty patients suffering from stable COPD who were treated in our hospital from September 2016 to June 2017 were randomly divided into intervention group (n=30) and control group (n=30). All patients received regular medical treatment and nursing care. Patients in the control group received regular breath training using three-ball device (15 min/time, 2 times/day), while patients in the intervention group received enhanced three-ball breath training(15 min/time, 4 times/day). Pulmonary function (FEV₁% and FEV₁/FVC) and other outcomes were compared after 12-week breath exercise between the two groups. Results No statistical difference was found in baseline characteristics between the two groups(P> 0.05). FEV₁% and FEV₁/FVC of patients in both group improved compared with baseline. After exercise, FEV₁%(69.60±1.02) vs (62.33±1.99), P< 0.01 and FEV₁/FVC(64.33±0.93) vs (58.00±0.96), P< 0.01 in the intervention group were superior to control group. In terms of outcomes of SaO₂, 6 minute walking test (6MWT), COPD Assessment Test (CAT)score and BORG score, patients in the intervention group were better than those in the control group (all P< 0.05). No statistical difference was found in adverse events. Conclusion Patients receiving enhanced three-ball breath device training have better pulmonary function compared with those receiving regular three-ball breath device training.