The judicial system has a close relationship with order and security in any society; In such a way that any inefficiency or disruption of the justice system will cause social and security crises. The subject of this research is that Mansoor, the second Abbasid caliph (136-158 A.H.), who was infact the designer of the future of this caliphate, considering the importance of the function of the judiciary in resolving conflicts and establishing security and social order, how he used The function of this institution to create peace in the early society of the Abbasid era. Therefore, the purpose of this research is to investigate the role of the judicial system in the order and security of Baghdad during the Caliphate of Mansour Abbasi, with a descriptive-analytical method. The findings of the research show that Mansoor, by empowering the judicial institution by appointing judges with sufficient capacity, strengthening its related institutions such as Shurtah and Hesbah, and effectively using its security capacities, made the judicial system function to create security.and order in the newly founded city of Baghdad.