Obstructive sleep apnea syndrome (OSAS) is a common disorder characterized by recurrent obstruction of upper airway, leading intermittent oxygen desaturation and repetitive arousals during sleep, which can cause enhanced sympathetic activity, elevated levels of vasoactive substance concentration and vascular damage, and therefore, increase the risk of hypertension Continuous positive airway pressure (CPAP) prevents the airway collapse, avoids the occurrence of intermittent hypoxemia and arousal, is the preferred treatment for OSAS and has been widely used in clinical. In theory, CPAP maintains upper airway patency and preserves ventilation, thereby inhibits the chain reaction over activation of the sympathetic nervous system and blood pressure regulating mechanism, thus CPAP treatment have adequate scientific basis to cause a substantial reduction arterial blood pressure, but controlled studies showed either no effect or only a minor decrease in arterial blood pressure by 1.4 and 2.5 mmHg respectively.The current, which type of combination of hypertension OSA patients can obtain the best antihypertensive benefit from CPAP therapy is still under debate.