Post-traumatic stress disorder (PTSD), with the principal manifestations as invasive thinking, avoidance, negative emotions and cognition, and increased alertness, is a psychological disorder occurring after traumatic events. Sleep disorders are also considered as one of the core characteristics of PTSD. Previous studies have partly revealed the relationship between PTSD and sleep disorders, but the physiological mechanism of the relationship is still unclear. This article provides an overview of the clinical and physiological characteristics of PTSD and sleep disorders. Based on this, the bidirectional relationship between PTSD and sleep disorders is discussed, and the relevant physiological and brain mechanisms of the relationship between them are further explored. Future research needs to explore the neurophysiological mechanisms underlying the bidirectional relationship between PTSD and sleep by exploring the brain regions and neural circuits associated with both PTSD and sleep, providing more information and methods for the prevention and treatment of PTSD and sleep disorders.