Public finance law is a plural concept. This is due to its genesis and development through a specific historical and temporal context. Therefore, understanding its components and especially the legal framework of budget systems would not be complete, except through the study of its historical development. Institutionalism as a branch of political economics, because of the existing conditions of developing countries and its emphasis on the history and institutions of those countries, has a sufficient capacity to be considered as an appropriate theoretical tool to study and improve failures of the budget system. In this article, a historical analysis of legal framework of budget system in Iran will be offered. Keywords