Objective To explore the relationships among sedentary behavior, sleep quality, and frailty in older person with COPD.Methods A convenience sample of 273 older patients with COPD were invited to complete the Pittsburgh Sleep Quality Index, the Sedentary Behavior Questionnaire for the Elderly and the Tilburg Frailty Indicator.A structural equation model was developed to examine the mediation model hypothesis using Amos.Results Older patients with COPD scored （6.57±0.76） for frailty and （13.43±1.26） for sleep quality.They also reported spending （8.75±0.56） h/d on sedentary behavior.Sleep quality partly me-diated the relationship between sedentary behavior and frailty, accounting for 31.19% of the overall effect.Conclusion Sleep quality exhibits an incomplete mediation effect on the relationship between sedentary behavior and frailty in older COPD patients.Interventions should be taken to reduce sedentary behavior and enhance sleep quality, thus to prevent or delay the development of frailty.