Fight-or-flight response is a series of behavioral and physiological reactions triggered by life-threatening stress. These reactions enable individuals to escape from or defend against environmental threats, thus increasing the survival rate in dangerous situations. Stong or repeated fight-or-flight response sometimes causes a type of mental disorder, namely post-traumatic stress disorder (PTSD). Frequent natural disasters and traffic accidents have endangered Chinese people with PTSD. PTSD treatment calls for understanding the fundamental neural circuit mechanisms underlying fight-or-flight response.In this review, we will summarize recent progress in this field, and emphasize the significance of this research field in the China.