Posttraumatic stress disorder (PTSD) is a psychiatric disorder which cause is certain, and mechanism of PTSD has been studied actively for decades. The various kinds of therapy, based on the pathophysiology of PTSD, were applied and among them eye movement desensitization and reprocessing (EMDR), therapy for sleep, transcranial magnetic stimulation (TMS) and psychopharmacotherapy that showed considerable effect for patients with PTSD would be introduced.