Sudden death in epilepsy was once overlooked, and in recent years SUDEP has gradually gained attention with the reduction of mortality as an important goal of epilepsy treatment. SUDEP is now more uniformly defined as death that is sudden, unexpected, with or without witnesses, non-traumatic and non-drowning, with or without evidence of seizures, excluding persistent status epilepticus and excluding toxic and structurally abnormal causes by autopsy. The National Institutes of Health/National Institute of Neurology and Stroke Task Force recommends the following diagnostic categories: (1) Definite SUDEP (Definite SUDEP): i.e., other causes of death are definitively ruled out by autopsy; (2) Probable SUDEP (Probable SUDEP): non-autopsy, but meets the definition; (3) Possible SUDEP (Possible SUDEP): non-autopsy, but meets the definition; (4) Probable SUDEP (Possible SUDEP): non-autopsy. (3) Possible SUDEP (Possible SUDEP): SUDEP cannot be excluded, but there is no sufficient evidence to specify the cause of death. The term “Near-SUDEP” is used to describe cases in which SUDEP would have occurred without resuscitation intervention. Clear and uniform definitions and classifications are important for our research on SUDEP. The incidence of SUDEP has been reported inconsistently due to differences in the population and methods of study and inconsistent diagnostic criteria for SUDEP. The rate of sudden death is 20 times higher in patients with epilepsy relative to the normal population. Several studies have shown SUDEP to be approximately 0.9-2.3/1000/year in the general epilepsy population, 1.1-5.9/1000/year in the chronic epilepsy population, and up to 6.3-9.3/1000/year in those who are candidates for epilepsy surgery or who still have seizures after surgery. Data from case-control studies suggest that risk factors for SUDEP include frequent tonic clonic seizures (especially nocturnal seizures), polypharmacy, young age of onset, long duration, male gender, and symptomatic etiology.Aurlien et al. reported 10 of 26 SUDEP patients on lamotrigine, 9 of which were female patients on lamotrigine, with a higher incidence of SUDEP than female patients not on lamotrigine. However, some experts dispute this, arguing that the evidence is not strong. A recent controlled study (12 cases of SUDEP in 7734 patients using lamotrigine) suggested no significant difference in the incidence of SUDEP between patients using lamotrigine and controls. The pathogenesis of SUDEP is not fully understood, and possible mechanisms include cardiac arrhythmias, autonomic depression, seizure-related respiratory failure, post-seizure cardiomyopathy, and brain dysfunction. Animal studies suggest that the 5 serotonin system is involved in lowering the seizure threshold and increasing the risk of sudden depressive death. Effective antiepileptic therapy is the best way to prevent SUDEP. Effective medication can reduce the risk of sudden death by up to 7-fold. Before choosing an appropriate antiepileptic drug, a heart rate variability test is performed so that drugs with cardiac excitability effects can be carefully selected. Other methods such as surgery and vagus nerve stimulation to control seizures still need further research to prove whether SUDEP can be prevented. EEG-synchronized cerebral oxygen monitoring may be useful in assessing the risk of SUDEP, but studies with large samples are still needed. Oxygen administration interventions early in the seizure can help reduce the occurrence of respiratory disturbances and post-ictal EEG suppression. Another important approach to SUDEP prevention is education. Educate patients and families to properly understand SUDEP, assess risk, and provide options for emergency management of tonic clonic seizures. For high-risk patients, home seizure warning devices should be established, home oxygen and pulse monitoring should be instructed, and emergency management should be trained. The current domestic understanding of SUDEP is mainly derived from foreign literature reports and domestic case summaries. We hope that clinicians should pay attention to and improve the understanding of SUDEP, establish a SUDEP case presentation system, study the establishment of a reasonable SUDEP risk stratification method, explore SUDEP-related genes as well as patient education and family support, so as to ultimately reduce the occurrence of SUDEP.