The constitution is the foundation of the national legal system. It has been established for the protection of the individual rights and to ensure the system of independence of powers. To protect this fundamental document and to prevent any deviations or violations of the constitution could not be attained unless an ultimate interpreter has been predicted. Normally, such task vested on the supreme courts, the constitutional courts or the constitutional councils. The federal constitutional court of Germany (FCC) as guardian of the constitution with the goal of ensuring that all agencies follow the constitution was established in 1951. This Court is considered as a mechanism for ensuring public order and for the preservation of the values ​​and principles of the German legal system, particularly the fundamental rights and democratic principles. The constitution is the only criterion for the court decisions.In this paper, we propose a comparative study of the structure and functions of the FCC as corresponding institution to the Guardian Council of the Constitution of the Islamic Republic of Iran (Shora-ye Negahban-e Qanun-e Assassi).