The current study aims reduction cognitive vulnerability and dissociative experiences in Patients with PTSD by MEmory Specificity Training. in the Semi- pilot with pre test-post test and follow up after one month, Combined control group,24 patiens (12 men & 12 women) Suffering of PTSD, selected via available sampling and were Randomly in experimental and control groups. Subjects in experimental group received MEmory Specificity Training in 4 sequential weekly sessions and control group Were placed in Waiting list. In both groups, Scores Were collected before and after the intervention and with month follow-up period by Dissociative Experiences Scale (DES-II), Autobiographical Memory Test (AMT), Impact of Event Scale-Revised (IES-R), The data were analyzed by Multivariate analysis of variance with repeated measures. findings Confirmed Effectiveness of MEmory Specificity Training That  reduction cognitive vulnerability Related to avoidance, intrusive thoughts, Hyperarousal and reduction dissociative experiences in Dissociative Amnesia, Depersonalization/Derealization and Absorption/Imginative Involvement  dimension in patients with PTSD.