The Organisation of Ismaili Dawa which had hierarchal structure, brought about a great success for Ismaili Dawa in the Islamic world. After the Fatimids came to power, the Dawa as an active and efficient organization, first in Maghrib and then in Egypt, remained in the administration until the end of its reign. This organization had direct relation to political and religious transformation of the Fatimids and its success influenced permanence and stability of the Ismili Dawa. This paper intends to study the following questions: 1- What was the structure of Ismili Dawa? 2- How was the function of the organization? 3- Why, after the Ismaili succeeded, was the propaganda division of the organization not ended? 4- How was the process of transformation in the organization since its establishment? 5- What was the function of the Da'i outside the Fatimid′s reign?