The formation and alliance of North Atlantic Treaty Organization (NATO) in the Cold war era, especially after the war, had been one of the keys and controversial issues of the international relations researchers. The explanation for the reasons of formation and alliance of this organization is formed in three theories which are, realism (classic and new), liberalism (classic and new) also social constructivism, in different ways. This article, meanwhile investigates weight of each of these three theories, it is trying to present a theoretical framework compilation which is able to be a more efficient explanation of the alliance of NATO, especially after the cold war.Based on combined framework, in analyzing the causes of the continuation and development of this organization, we must consider the factors like; the anarchic structure of the international system, the polarity of the international system, the role of major powers in the system, the position of the international institutions as well as the internal factors and forces and the domestic policy in the process of formation and alliance of the unions like NATO. Meanwhile, mental phenomena, material factors must be measured together and be investigated entirely. In this kind of explanation, different factors at different levels, to understand trends alliance of NATO are considered. Eventually, in explaining this issue, the role of identity, especially the process identity which based on that, western identity with a particular interpretation of democratic values in front of non-western identity with different values is considered. In fact, this dual identity results to alliance the organizations like NATO that its aim is to protect the constructed identity in front of Lt. made identity.