Abstract: Nitric oxide (NO) is widely present in peripheral and central nervous system and regulates many physiological functions. Sleep-arousal is an advanced physiological activity. Studies have shown that NO is involved in the regulation of sleep and arousal. Nitric oxide synthases (NOSs) are a family of enzymes that catalyze the production of NO from L-arginine. Through guanylate cyclase or S-nitrosation of protein, NO can affect the activity of the ascending reticular activating system to regulate the sleep-arousal process. This paper summarizes the production of NO, its effect on sleep-arousal and its mechanism in the ascending reticular activating system, and provides new ideas and directions for the study of sleep and arousal.