Concerning Imamah of ‘Ali (PBUH) and other Imams (PBUT), there are two views: first, their Imamah is proved through [the principle of] Imamah and in the other it is proved through [the principle of] Shura. In the present writing, to explain the role played by Shura in Imamah, the author introduces his points under three categories: 1ـGodـthe Glorifiedـand appointment of Imam; 2ـStudy of Caliphate and Imamah of Abu Bakr and ‘Umar; and 3ـthe time of introduction of Shura theory. Explaining these three categories, the author goes to provide pieces of evidence for the theory of Shura from the Holy Quran and the Holy Prophet’s tradition.