The purpose of this study was to determine the legal position of the Court The Constitution as a Negative Legislator in Law Testing; and to know the juridical construction of just constitutional law enforcement. The research methods used are qualitative methods and juridical approaches normative. The results showed that the birth of Law Number 8 of 2011 concerning Amendments to Law Number 24 of 2003 About the Constitutional Court is considered to limit the authority of the Constitutional Court and some of the core Articles he amended and added. DPR as in Article 50A. Furthermore, as a result of the adoption of the separation of power system, institutions The state is no longer qualified into the highest institutions and higher institutions of the state. The principle of strict separation of powers between the legislative, executive and branches judiciary by prioritizing the relationship of checks and balances between each other. While the juridical construction of constitutional law enforcement towards substantive justice is found in every decision of the Constitutional Court.