Objective To investigate the application of a convenient, reliable and effective method for diagnosis and therapy of sleepbreathing disorders in clinic. Methods 52 snorers who were suspected of having sleep apnea syndrome (SAS) were monitored by Auto setCPAP system in diagnost ic mode. We divided 43 cases who accorded with SAS diagnostic standard into two groups by AHI or LOSAT, which werelight to moderate SAS group and sever SAS group. Their relied parameters were compared 10 patients with moderate - sever SAS we re treated byAuto set CPAP system in therapeutic mode. Results Auto set CPAP system could record main parameters to diagnose SAS in diagnostic modeSimultaneously SAS were distinguished into different degrees according to the monitoring results After treatment, patients' sleep quality wereimproved, AHI dropped and LOSAT ascended significantly and the time for Flating Index (FI) below 0. 15 or 0. 10 was reduced ( P < 0. 001 ).Average leak for nasal mask is below 0. 4L/sec. Conclusion Auto set CPAP system is convenient in its manipulation, the work strength fortechnician is low and disturbance to patient's sleep is little. Auto CPAP titration can raise patient's compliance to CPAP treatment so it is worthto be applied to clinical work widespreadly.