Within each legal system, there is a set of legal institutions whose order and quality of relationship are directly related to the efficiency and dynamism of that system. Public law and public law are among the legal institutions that were recognized in the Iranian legal system. In the Constitution of the Islamic Republic of Iran, these legal institutions were mentioned as the general framework of the legal system. The main subject of this research is the analysis and description of the substantive and legal foundations of public law and the legal rights of public law. Using descriptive-analytical method and analysis of issues such as the logic governing law and the principles governing the interpretation of laws, this research seeks to find an answer and remove the ambiguity for the question of what is the difference between intrinsic characteristics, nature and legal basis of legal institutions There is public law and public law, and to what extent does the constitution reflect the characteristics and nature of these legal institutions? The findings show that the logic governing public law is of the type of polemical logic and the interpretation of the rules related to this institution is of the type of broad and free interpretation. The logic governing public law is of the type of formal logic and the method of interpreting its rules is of the type of narrow and limited interpretation. There are principles in the Iranian constitution that contain these legal institutions that can be identified from their relationship with other principles through their inherent characteristics and nature.