ObjectiveTo study the effect of noninvasive positive pressure ventilation (CPAP) treatment on the perioperative period of obstructive sleep apnea hypopnea syndrome (OSAHS), and to explore the clinical significance of CPAP in reducing surgical complications. Methods Thirty-six patients with OSAHS underwent preoperative diagnostic and multi-channel sleep monitoring under CPAP treatment, and the changes of sleep structure, respiration, oxygen saturation and microarousal were analyzed before and after CPAP treatment. Results: After CPAP treatment, all the indexes were significantly improved compared with the pre-treatment, the sleep structure of the patients tended to be normalized, the stage 1 light sleep was reduced, the stage 3+4 deep sleep and the REM stage sleep were significantly increased; the micro-wakefulness, respiratory events and the decrease of oxygen saturation were significantly reduced; the changes of all the indexes of the patients with mild, moderate and severe OSAHS were somewhat different. After CPAP treatment, open-mouth breathing was reduced, and at the same time, through preoperative local drug nebulization of the pharyngeal cavity, the patients’ pharyngeal cavity congestion was significantly reduced, intraoperative and postoperative bleeding was not much, and there were no serious complications, such as hypertensive crisis. Conclusion Perioperative CPAP treatment can effectively improve the sleep structure of OSHAS patients, and achieve the purpose of stabilizing hemodynamic changes by correcting respiratory disorders and oxygen saturation decline, which is of great clinical significance in improving surgical and anesthetic tolerance and reducing perioperative risks.