Syncope is a common clinical condition that involves many causes and complex mechanisms. In recent years, there have been great advances in its diagnosis and treatment. In 2004, the European Society of Cardiology (ESC) revised its 2001 guidelines for the diagnosis and treatment of syncope, in 2006 the AHA/ACCF published a statement on the evaluation of syncope, and in 2006 the journal CIRCULATION published the results of the POST trial, which overturned the previous conventional understanding. The conclusions of the POST trial published in the European HEART PACING journal in 2003 were rejected. Therefore, it is necessary to make a summary of the diagnosis and treatment of syncope. I. Initial evaluation: This includes: careful history taking, physical examination (including blood pressure measurement in the upright position), and 12-lead ECG examination. The primary question to consider: Is it a true syncope or a “non-syncopal” syncopal-like disorder? Syncope is a transient loss of consciousness (TLOC) due to transient ischemia and hypoxia in the cerebral cortex, usually lasting from a few seconds to several minutes. This is to be distinguished from coma and vertigo. The latter is a prolonged loss of consciousness. In contrast, vertigo is not accompanied by loss of consciousness. In addition to syncope, transient loss of consciousness can be seen in: 1. metabolic diseases: e.g. hypoglycemia, hypoxemia, hyperventilation with hypocapnia (e.g. hysteria); 2. epilepsy; 3. poisoning; 4. transient ischemic attack of the vertebrobasilar system. In addition, syncope should be differentiated from certain syncope like disorders: 1. falls; 2. episodic sleep disorders; 3. sudden collapse episodes; 4. psychogenic pseudosyncope; 5. transient ischemic attacks of the carotid system. In the general population, the most common cause of syncope is reflex syncope, followed by primary cardiac arrhythmias. The causes of syncope are closely related to age: reflex syncope, psychogenic pseudosyncope, and primary arrhythmias (e.g., long QT interval syndrome or preexcitation syndrome, BRUGADA syndrome) are more frequent in children and young adults. Reflex syncope is also the main cause of syncope in middle-aged and elderly people, such as swallowing syncope, urinary syncope, defecation syncope and cough syncope, with a higher incidence of postural hypotension than in younger people. Arrhythmic syncope based on aortic stenosis, pulmonary embolism, or organic heart disease is more common in the elderly. Only typical vasovagal syncope has precipitating events, such as extreme fear, severe pain, grief, blowing, prolonged standing, and other typical precipitating factors.