"Power structure" in all governments has been considered as one of the factors influencing the stabilization or destruction of that system. Hence, the composition of governance in the Islamic Revolution of Iran, which evolved from religious teachings of the Twelver Shia in 1979 A.D; It has usually been under consideration of thinkers. According to the teachings of the Shia school, the thought of Imamate and Mahdism determines the power structure. After the triumph of the revolution in Iran, the governance of the Islamic Republic was elected via the people and with the vote of the people, constitutional professionals had been shaped and the constitution was formulated. In this article, the function of the doctrine of Mahdism, in the shape of the power structure, will be defined in a descriptive-analytical way, relying on the principles of the constitution. In a general perspective, the centrality of the concept of Imamate and Mahdism and the concept of “Guardianship of the juris consult” (Wilāyat al-Faqīh) in the age of the occultation and the congruence of the plans and desires of the Islamic revolution is accentuated in the plans of the promised government. In addition to the generalities raised about the doctrines of Shiism and Imamate in the constitution, reviewing  some programs and goals set in the constitution and their congruence with the packages of the promised government, such as the enhancement of moral virtues, scientific growth, the expansion of equity and justice, economic growth and the removal of poverty, freedom and security, refutation of arrogant and helping for the oppressed, and the restoration of civil rights shows the high function of the doctrine of Mahdism in this revolution. In general, it can be stated that the "Imamate and Mahdism doctrine" is the foundation of Islamic republic of Iran, and the strength of this government is structured on this basis.