The name of Iranians were associated to Abbasian’s caliphate for the political and cultural services which they have done during the history. Despite Iranian’s special services which were done in the early years of the Abbasid Caliphate, they faced and tasted their bitter sword. As a result, a group of Iranian families were still loyal to the Abbasians and were at the head of the official institutions, and some others revolted against them. Iranians cooperated with Arabs during the Abbasian’s movement because they hope that they will choose someone from the members of the family of the Prophet to have the power, so he would treated them according to the laws of Islam. But soon after the establishing of the Abbasian’s Caliphate and by killing of Abu Muslim, they found that all their efforts were futile. Abbasian, particularly Mansour followed Omavian in being cruel to people. After that, big movements like Sandbad, Ebn Maghna, started to happen in which they were not only hated Abbasian’s caliphate but also they denied the religion that they propagated and propagandized. However, during the Mansur’s caliphate some Iranian families like Barmakians and a number of Iranian characters were in collaboration with Mansour and helped them to hold over Abbasian’s caliphate. They gave them a lot of spiritual and administrative assistance and of course they paid off as a result of their service in the time of Harun al-Rashid’s caliphate. The Iranians intellectually and scientifically were the backbone and the base of these concepts and of course scientific builders of Islamic civilization in the Abbasian’s era. Most scientists were introduced to the Muslim’s world from these zones.