Objective To analyze the clinical features of chronic obstructive pulmonary disease(COPD) patients with or without obstructive sleep apnea-hypopnea syndrome(OSAHS)(overlap syndrome),and compare the status of sleep-disorder breathing between outpatients and inpatients of them.Methods A total of 300 patients with stable COPD were screened for sleep disorder breathing using questionnaire,Epworth sleepiness scale(ESS) and home pulse oximeter testing.Those with ESS≥10 or oxygen desaturation over 4% per hour sleep >5 times were under further PSG testing.Results there was significant difference on sleep-disordered breathing index,body mass index,heart rate in sleep,the percentage of the recording time spent with arterial oxygen saturation(SIT90),the nocturnal mean arterial oxygen saturation and the minimal arterial oxygen saturation between COPD outpatients and inpatients clinics.Conclusion Sleep-disordered breathing can affect and aggravate patient’s condition of COPD.