The event-related potential (ERP) is considered as one of the most effective methods to study and analyze objectively human mental activity based on nerve electrophysiology. At present, ERP is not only used in the study of lie detection, but also in the clinical medicine for the cognitive assessment on patients with cerebrovascular disease, dementia or traumatic brain injury and auxiliary diagnosis of mental illness. With the further development of ERP detection technology, it would have a wider application prospect in the field of forensic medicine.