Abstract: Event-related potentials (ERPs), which were evoked by visud (image) and auditorystimuli, were recorded in 61 patients with closure cranio cerebral trauma. The P3 latency of which was significantly prolonged compared with the matched control (P0. 001 ). The P3 latency and amplitude in ERPwere closely related to the severity of the disease. ERPs were recorded in 31 of the patients repetitively andmarked difference was found between the former and the latter results (P0. 001 ). It suggests that ERPcan be taken as an objective index on observation of the extent of the defeciency and recurrence of the braincognition function in patients with colsure craniocerebral trauma.