Objective:To investigate the outsets and manifestation of sleep disorders in stable phase of COPD patients combind with SAHS (Sleep Apnea/Hypoventilation Syndrome),so as to improve the understanding of origin and clinical features of COPD from the aspect of sleep medicine. Methods:124 stable phase COPD patients were subjected to continuous blood oxygen saturation measurement during the sleep without any oxygenation. Multi-lead polygraph examination was performed to obtain ODI and AHI (ODI>5 incidents per hour or AHI≥10 incidents per hour as a diagnostic standard for SAHS). 64 COPD patients without any complications were selected as control. These controls were paired with the above COPD patients who were complicated with SAHS, according to their age, gender and WI (Weight Index). The features of sleep disorders were analyzed by comparing the individuals in the paired groups. Results:27.4% of the 124 patients with COPD (34/124) had overlapping syndrome (COPD + SAHS). Statistically significant differences were found between the two groups among AHI, pattern of sleep disorder, ODI/AHI % and SIT90%,SIT85%,SIT80% (the percentage of sleep time when SpO2<90%,85%,80% to the total sleep time). Conclusion:It was estimated that there were about 25%～30% of stable COPD patients with overlapping syndrome presently in our country. Comparing with the uncomplicated COPD patients, the OS had severe sleep disorder pattern, predominantly the hypoventilation types. The OS had more severe hypoxemia. SIT90%,SIT85% and LSpO2 were the most sensitive indexes for hypoxemia in OS patients during the sleep.