Continuous positive airway pressure ventilator (CPAP) was designed more than 50 years ago for the treatment of obstructive sleep apnea syndrome (OSA). CPAP owns the best evidence in both short-term and long-term treatment outcomes. Hypertension, atrial fibrillation, cognitive dysfunction, stroke, glucose control, lipid profile, and renal and liver function all have significant improvement after the CPAP treatment. Acceptance and compliance were still the problem for the use of CPAP. New developments including bi-level positive pressure ventilator (BiPAP), auto-adjust positive pressure ventilator (APAP), as well as comfort design on mask and performance were introduced, which make the acceptance and compliance better than before. Although they are minor, some complication were reported, which need physicians to take care. More efforts are needed for the CPAP development on the treatment of OSA.