This research tries to provide a model for studying the transition in the defense industry. To this end, using Bourdieu's multilevel perspective and theory of action and reflecting on the facts obtained through study and discussion with experts, a framework for understanding long-term developments is presented, called the "Triangular Understanding Framework". According to this framework, in order to understand the transformation in the field and the habit of the defense industry, three aspects or three important steps must be considered: "establishment", "threshold" and "routing towards sustainability". These three concepts help us to make three effective cuts to the development and transition of a socio-technical field. The claim of this study is that reflection on how to start and establish, threshold and sustainability of a socio-technical field is our most important way to understand the current situation and the direction of its future developments. Without understanding these three situations, the policymaker steps into the tortuous path of transition management with an aura of ambiguity. The perspective of this research helps to modify and promote the multilevel perspective in two ways, which is mentioned in the final section.