Since foreign policy is formed in a changing environment, it is usually regarded as a specific kind of the players’ political behavior which is characterized by constant change. Therefore, it is believed that no fixed principle can be found in it. However, the fixed principles in Islamic discourse of the foreign policy, has made some people criticize it as rigid. It is hypothesized here that “fixed principles” are among the important bases of a successful foreign policy. In the first part of the article, the patterns of foreign policy are analyzed. In the second part, the author describes and discusses the fixed principles of Iran’s foreign policy. Therefore, these fixed principles are defined in three different levels of the idea of foreign policy, the behavior of foreign policy and the organization of foreign policy.