Identity, values and norms are among the main elements building interests of countries in foreign policy and international relations. Any change in them may lead to change in priority of interests as well as the approaches and orientation of foreign policy. It seems Islamic Republic of Iran's foreign policy which is deeply rooted in values and causes of Islamic revolution is not an exception and despite the change of governments these identity elements have "continued" and no "change" has occurred in their foundations. Having this in mind and having known the identity and epistemological foundations of Islamic Republic of Iran's foreign policy, the current article tries to prove its claim applying "comparative" method in its three specific periods as following: 1-economic renovation period, 2-reform period and 3-conservatism.