The orexin (hypocretin) system is a hypothalamus-specific neuropeptidergic network that integrates metabolic, emotional, and environmental cues to regulate sleep-wake states. By activating arousal-promoting nuclei and inhibiting sleep-promoting regions through widespread downstream circuits, it plays a crucial role in the initiation and maintenance of wakefulness. Orexin system also plays a crucial role in regulation of rapid eye movement sleep. Loss of orexin function is closely associated with narcolepsy, characterized by fragmented wakefulness and emotionally triggered cataplexy. This review summarizes the current advances in the neural mechanisms underlying orexin-mediated regulation of the sleep-wake cycle, aiming to provide a theoretical basis for precision interventions in sleep disorders.