Objective:To investigate the status of brain evoked potentials (BEP) and the relationship between BEP and psychiatric symptoms before and after treatment in patients with post-traumatic stress disorder (PTSD). Methods: P_(300), auditory evoked potential (AEP), visual evoked potential (VEP) of BEP, Symptom Checklist-90 (SCL-90) and Impact of Event Scale (IES) were used to evaluate 86 patients with PTSD (PTSD group) and 56 normal controls (control group), PTSD patients were followed up with the same markers after 3.5 months treatment.Results:Compared with the control group, PTSD patients showed delayed latency and increased amplitude of P_(300)-P_3, delayed AEP-N_2 latency, and delayed VEP-P_2 latency. Shortened latency and decreased amplitude of P_(300)-P_3, and shorted VEP-P_2 latency were found after treatment. The mostly items of BEP were significantly related to psychical symptoms before treatment, and the changes of BEP were significantly related to the alleviation of psychical symptoms after treatment.Conclusion:BEP might be state markers of PTSD. The clinical application of BEP in PTSD is emphasized.