There is a dualism of justice, namely traditional and modern justice. Various authors note that there are legal problems that live in a society which are considered sidelined. On the one hand, there is also an assumption that the legal system that has been built has suppressed the existing system. Even though it is acknowledged that the justice system no longer recognizes customary courts institutionally, this becomes an issue of how the process of internalizing the law that lives in society into the Indonesian criminal justice system. This study uses a normative juridical research method, namely a legal research method that only examines literature or secondary materials (Soerjono & Sri, 1994; Roni, 1994; Achmad, 2009). The research results show that the hybrid Justice System is a model of law internalization that lives in society. In Indonesia, it is a reality that exists without design. The dualism of the justice system, primarily criminal justice, where on the one hand, the formal legal system works based on the principle of legality, while on the other hand, there is customary law as a living law in society.