The most common causes of syncope in young people are the following three: 1, vascular regulatory mechanism disorders, the most common syncope is vasovagal syncope, which is caused by abnormalities in the vascular regulatory mechanism, the patient syncope and postural changes, or a history of prolonged standing, emotional excitement, etc., resulting in vasodilation, blood stays in the body circulation, causing transient whole-brain ischemia, resulting in the patient fainting, which generally does not require special treatment. Cardiac syncope is second only to vasovagal syncope and is commonly caused by serious arrhythmias, such as bradycardia or A.S. syndrome caused by pathological sinus node syndrome, and the improvement of dynamic ECG, vascular ultrasound, cardiac ultrasound and foam test can help to clarify the cause. The serious organic diseases such as brain tumor, encephalitis.