The aim of this study is to shed light on the direct and indirect causes that have contributed to weakening the Abbasid State and then fall, and see events in this stage, as the study presents the roles of some characters who have played a prominent role in this stage such as Abbassi almtakhreyen, Ibn alelkomy, Nasiruddin Tusi and some Princes parties. In order to discuss these reasons in a way closer to objectivity, the researcher had relied on primary sources and some modern references, and followed the historical approach based on analysis and extrapolation of some historical novels. This study contains an introduction, preface, three chapters, and a conclusion. The chapters are, Chapter 1 policies last from Abbassi (622-656/1225-1258 m), the second chapter in the impact of the relationship between the Central and the Mashreq States succession, while chapter ill focused on: the emergence of the Mongols on the political scene and the fall of the Abbasid State (656/1258). The study concluded several results for example, know the Abbasid State provisional boom during the reign of the Abbasid Caliph Al-Nasser to the religion of God through system (bully Nasiriyah). Personal weakness ingeniously latecomers and living in luxury led to a role for their comment on a firm grasp of Things in the State and continued competition. Disintegration and Division that experienced the Abbasid State in late days led to the Independence of many States such as algorithm and Ayyubid and Ismailia lawn, Doctrinal and sectarian conflicts have had a prominent role in weakening the Abbasid State constant rivalry between doctrines, especially Sunni and Shiite which has undermined the Abbasid State body inside and force the enemy. Experienced by the Islamic world in General and the Abbasid State in particular were known for Moguls events and cruelty as the Abbasid State could face this enemy, Conflicting views of historians about cases of alelkomy Minister agreement with Mongols to drop the Abbasid State and Nasiruddin Tusi motivated the Mongols to drop the Abbasid State. Also Fear of the Lords from the Mongols and their desire to preserve their property was pushing them to provide obligatory obedience and allegiance to the Mongols and assist them in the Elimination of the Abbasid State. At the end the physical loss, social and scientific to the Islamic world after the fall of the Abbasid State in the hands of the Mongols.