Syncope is a transient ischemia of the entire brain resulting in impaired consciousness. Its onset can be followed by rapid recovery of consciousness without leaving focal signs. Syncope lasts for a short period of time, approximately seconds to tens of seconds. The common causes of syncope are: vasodepressive syncope, cardiogenic syncope, and reflex syncope. Vasopressor syncope: It mainly manifests as a sudden onset of insufficient blood supply to the brainstem and the inability to maintain a normal state of consciousness due to ischemia of the brainstem reticular superior activating system. It causes transient ischemic attack. Cardiogenic syncope: the most serious cause of syncope, mostly due to severe rapid or slow heart rate arrhythmias, cardiac arrest, which can occur in any position and can be accompanied by limb convulsions and urinary and fecal incontinence in severe cases. Reflex syncope: This is due to autonomic dysregulation of vasodilatation. For example, postural hypotension can lead to transient cerebral blood supply disorder and cause syncope; a large amount of urination at one time or continuous coughing can cause syncope caused by a decrease in the amount of cardiac blood return; hypoglycemia and severe anemia can also lead to syncope. In conclusion, no matter what the cause of syncope is, the patient should be immediately put in a lying position, avoid sound and light stimulation, relax emotionally, and go to the hospital for examination and treatment of the cause of syncope in a timely manner.