Mazidians were one of the Shiite rulers in Iraq who governed on Hellah region and its surrounding during the years 350 -545 A.H/961-1150 A.D. They were regarded as a branch of Bani Asad Arabs who first took up position in a place between Kufah and Hit and were elasping their times by means of animal husbandry and farming. Until, during the Buwayhid’s Muez – ud – dauleh era, Ali ben Mazid could estabilish Mazidian government in above – mentioned areas under the protection of Buwayhids. After Ali, seven other men of Mazidians’ house gained access to government and with peaks and valleys, ruled over Mazidian territories. Undoubtedly, Sadaghate ben Mansure was the greatest and the most famous ruler who had Mazidians’ government in his hands, contemporary to the advent of the Seljukid’s dynasty. He, which was an intelligent prince (emir), benefiting from differences and conflicts between the Seljukid princes, conquered Basrah, Kufah, Hit and Takrit cities, built the city of Hellah and transfered his capital there, and put it as a base for unquestioning supporting of the clerics and scientists, and procured ground for more than ago extending of Islamic civilization. The present article, in a descriptive – analytical method and by using resources, sources and historical researches, for the first instance tries to study the bases and qualities of the Mazidian government advent, afterwards express their part in deployment of Islamic culture and civilization, especially in two literary and scientific fields, and then explanate their activities in the direction of Shiism expansion.