The main objective of this work is to analyse Public Civil Action and Constitutionality Control in terms of the possibility of using Public Civil Action to declare a law or normative act unconstitutional, as well as to see if there is a likelihood of this institute taking over the exclusive prerogative of the Federal Supreme Court in terms of assessing constitutionality. To this end, in addition to a doctrinal perspective on the institutes of public civil action and constitutionality control, studies were carried out based on jurisprudential research by the Court of Justice of the State of Rio de Janeiro and the Federal Supreme Court.