The clinical manifestation of syncope is a transient loss of consciousness, which usually lasts for a few seconds, but individually can exceed one minute. According to its pathogenesis, it can be categorized into vasoconstriction disorder, cardiac syncope, cerebral syncope, and blood component abnormality. Fainting caused by pain belongs to vasoconstriction disorder, also known as vasopressor syncope, accounting for 70% of syncope, mostly seen in young and frail girls, seizures often have obvious triggers, such as pain, emotional tension, fear, minor bleeding, and so on. In hot weather, dirty air, fatigue, fasting, insomnia and pregnancy, etc. more likely to occur, before the syncope can have dizziness, vertigo, nausea, epigastric discomfort, pale, limb weakness, fidgeting and anxiety, etc., lasting a few minutes, followed by a sudden loss of consciousness, often accompanied by a drop in blood pressure, a weak pulse, lasting a few seconds or a few minutes, can be naturally awakened, no after-effects. The mechanism of occurrence is due to a variety of stimuli through the vagal reflex caused by transient vascular bed dilatation, reduced return blood volume, reduced cardiac excretion, blood pressure drop resulting in insufficient cerebral blood supply.