One of the main topics and issues current among contemporary religious scholars lies in explaining the domain of religion. Therefore, the problem of the present study is to explain the political scope of religion in Imam Khomeini's thought. As is known, a group of religious scholars consider the domain of religion limited to otherworldly affairs and agree with so-called religious restrictionism. In their view, the propositions of religion are focused on the happiness and goodness of the human in the hereafter world, while the formulation and organization of earthly affairs is not a part of religious mission. The present study, using a descriptive and analytical method, seeks to critique religious restrictionism with reliance on Imam Khomeini's political views and ideas, and based on the idea of comprehensiveness to need and educatin, support the view saying the realm of religion in all fields of human life.