History of Iran during the era of Al-e Buyeh (320-447 hijri) was one the most important periods of the mosque’s role in various aspects. Mosque as the most efficient Muslim religious institution, played a central role in the continuity of Muslims’ socio - political life, especially Iranians of Al-e Buyeh shi’i government. In fact the mosque played the role of power construction. Social – political history of Iran during this period has been under the influence of mosque and its functions. In this paper, the authors tried to explain the influential role of mosque in political changes of that period in Iran history alongside a description of the most functions of Mosques during the era of Al-e Buyeh. In this paper the mechanism of the efforts of Al-e Buyeh emirs to use the functions of mosque In order to establish authority and legitimacy has been studies. The results of this research show the frequent use of Al-e Buyeh government from mosque in many aspects to achieve their political and social goals, especially in Baghdad and important cities of Jebal states. Al-e Buyeh also benefited from mosque and its functions for legitimization, control of political protest and the reading of sermons.