Today, the modern concept of identity has become so comprehensive and vague that each person, according to his Adventitious and appointed positions, belongs to several minorities, and there are always people who share or have different interests in the experience of this "group identity". Although the existence of these various identities is the reality of our time, but in a world where nation-states are still the main political actor, the existence of group identities does not indicate the insignificance of the national identity. It seems that the dialectic between group identities and national identities - which is strongly influenced by the policies of each country's rulers - affect the quality of each other. The main question of this article is that how the approaches of absorbing or rejecting political systems towards group identities, which are referred to as "identity politics", affect individuals' perceptions of the national identity experience? Using descriptive-analytical method and library resources, the author seeks to assess the hypothesis that the identity policies of the Islamic Republic of Iran are formed on the basis of similarization and assimilation. On this basis, a kind of permanent rejection and denial of multiple identity groups is rippling in this country, that comes in the result of which is the social and epistemological rupture of various identities, weakening of empathy and cooperation between them, and the decline of the concept of Iranian identity.