Abstract: The unity of legal order means that all current national laws and regulations should be coordinated and consistent, requiring that legal acts stipulated by one departmental law should not be evaluated as illegal acts by another departmental law. This is what needs to be implemented in the process of modernizing the rule of law in China. important principle. However, due to the differences in the scope and tasks of legal regulation adjustment in different departments, the unity of legal order has not been realized. By analyzing the unified theory of legal order and the theory of illegal relationship, a “moderated” theory of illegal relativity should be recognized for the judgment of criminal illegality. Although criminal law is a post-law of civil law, administrative law and other legal norms, the post-law of criminal law does not mean that the judgment of criminal illegality is subordinate to the judgment of pre-law. The judgment of criminal illegality from the perspective of the unified legal order should be relatively independent. The judgment of criminal illegality is based on the overall independence of the three-level crime theory system. The behavior of criminal illegality means that it has the constitutive elements and is illegal, rather than being evaluated as illegal in the pre-requisite law. The independence of the judgment of criminal illegality is relative, and the pre-legal legality is the reason for preventing criminal illegality, which is embodied in the function and value of “incriminating” in the class that constitutes the necessary elements or the illegality.