There are several reasons for sudden dizziness: 1. It may be due to the existence of low blood pressure in the patient, for example, if the patient suddenly stands up after squatting, due to the squeezing of skeletal muscles and the effect of gravity, resulting in the patient’s blood gathering in the lower limbs and reduced blood circulation in the brain, there will be sudden dizziness; 2. It may be due to the existence of brain diseases in the patient, for example, brain tumor, cerebral infarction, brain tissue necrosis, cerebral stroke 3. It may be caused by a kind of dizziness caused by the patient not sleeping well at night, staying up late, or overexerting the body. Patients are advised to go to the hospital for examination and early diagnosis of the cause and then treatment. In daily life, they should pay attention to their mood swings and control their blood pressure. If the number of dizziness is more frequent, patients are supposed to undergo brain CT examination and, if necessary, surgery.