(1) vasovagal syncope (VVS): vasovagal syncope is the most common cause of syncope in children, accounting for about 80% of all children with syncope. According to our analysis of about 100 cases, this disease mainly occurs in girls aged 11-19 years old and usually manifests itself when the child is standing for a long time, or when the child sees blood, feels severe pain, is in a hot and stuffy environment, takes a hot bath, exercises or is stressed. The onset of syncope may be preceded by transient dizziness, inattention, pallor, decreased visual and auditory perception, nausea, vomiting, sweating, unsteadiness, and other aura symptoms. The upright tilt test is the accepted method for diagnosing and differentially diagnosing the disease. (2) Postural orthostatic tachycardia syndrome (POTS): The concept of POTS has only been introduced in children in recent years and is one of the manifestations of chronic upright intolerance, which can also lead to the occurrence of syncope in severe cases, and according to our study, POTS also accounts for a large proportion of unexplained syncope in children. According to our observations, the clinical features are that most children with POTS are of school age and the incidence is higher in females than in males. POTS is diagnosed by the following symptoms: dizziness or vertigo, chest tightness, headache, palpitations, facial changes, blurred vision, lethargy, morning sickness, and syncope in severe cases, which are relieved or disappear when the child is lying down; these symptoms often occur in the standing position, but they can also occur in the sitting position. The diagnosis of POTS is made by an increase in heart rate of ≥30 beats/min or a maximum heart rate of ≥120 beats/min within 10 min after HUT test or uprightness, accompanied by symptoms of uprightness intolerance, in addition to other underlying diseases that can lead to autonomic nervous system symptoms such as anemia, arrhythmia, hypertension, endocrine diseases and other cardiogenic or neurogenic diseases that cause syncope. (3) Orthostatic hypotension (OH): Orthostatic hypotension is defined as a significant drop in blood pressure within 3 min of tilt or uprightness, with a systolic drop greater than 20 mm Hg or a diastolic drop greater than 10 mm Hg. As the patient’s blood pressure falls significantly, the patient may experience dizziness, syncope, or aura of syncope. Our findings suggest that the disease is uncommon in children, and there is debate as to whether this definition applies to children, as some investigators have found that the reaction is seen in many normal children. The mechanism of the disorder is not clear, but it is thought that it is mainly due to autonomic dysfunction, so some authors have classified it as an autonomic disorder. (4) Situational syncope ① Swallow syncope: Swallow syncope is usually associated with esophageal or peripharyngeal injury or linguopharyngeal nerve palsy. The disease is not common in children. Swallowing syncope is mainly manifested as syncope or aura of syncope when the child swallows or swallows too hot or too cold food or even at the sight of food. The afferent branch of this reflex may be the sensory nerve fibers of the esophagus, and the efferent vagal activity response leads to bradycardia, sinus arrest or varying degrees of atrioventricular block. This disorder does not resolve spontaneously in children, but can be treated with parasympathetic drugs, or with surgical selective removal of the cardiac vagus nerve, or with the placement of a permanent pacemaker. Cough syncope: Dizziness, dizziness, and syncopal episodes may occur with coughing. Cough syncope is common in middle-aged people with chronic lung disease, but can also be seen in children with asthma or wheezing. The mechanism of this syncope is mainly the sudden increase in pleural cavity pressure and intracranial pressure, which leads to an increase in cerebrospinal fluid pressure, resulting in a decrease in cerebral blood flow and reflex peripheral vasodilatation; similar to the “Valsava” maneuver, it leads to a decrease in cardiac output and reflex excitation of the vagus nerve, resulting in atrioventricular ventricular conduction block. (iii) Micturition syncope: Micturition syncope is a syncope that can occur before, during, or after urination. It can occur in both adolescents and the elderly, and is more common in boys. Predisposing factors include low food intake, recent history of upper respiratory tract infection and alcohol consumption. Syncope usually occurs at night or upon awakening from urination, usually immediately after completion of urination, with few aura of syncope. Recurrent episodes of the disease are rare. The cause of the occurrence of voiding syncope is unclear and the presumed mechanism of its occurrence includes cardiac depression caused by vagal stimulation and excitation of visceral afferent nerves by a full bladder. This syncope does not usually require treatment because it is rarely recurrent. ④ Defecation syncope: The occurrence of syncope or aura of syncope during defecation is called defecation syncope. This is often indicative of underlying gastrointestinal, cardiovascular, or cerebrovascular disease. It can occur in children and can be recurrent, so the primary cause should be actively sought in this group of children. Hair-grooming” syncope: This type of syncope occurs in females, often while the child is brushing her hair, brushing her teeth, or blow-drying her hair. It is separated from other vasovagal syncope because the mechanism of its occurrence differs from typical vasovagal syncope and includes stimulation of the scalp causing trigeminal nerve excitation, pressure on the carotid pressure receptors, and obstruction of basilar artery flow when the head is lowered or tilted. In children the condition often occurs after a warm bath when the peripheral vasculature is already dilated. An upright tilt test is often positive. Treatment requires only proper water intake to prevent hypovolemia, and cooling and drying the body before combing the hair. (5) Carotid sinus hypersensitivity: Carotid sinus hypersensitivity is rare in children, while the incidence in the elderly is about 10%. Syncope occurs mainly due to vagal hyperexcitation caused by slight pressure on the carotid sinus, resulting in sinus bradycardia, sinus arrest or atrioventricular block, leading to syncopal episodes.