Abstract: The principle of unity of law and order has sufficient theoretical and legal basis, which not only binds legislators, but also applies to judges or interpreters. The principle of unity of law and order cannot provide support for the appeal of conceptual consistency, nor can it effectively coordinate the evaluation of “legality” or “illegality”. The unity pursued by this principle is negative, and it does not play a positive role in the interrelationship between two specific norms, but strives to maintain the diversity of evaluation differences without departing from the overall value goal. The so-called non-contradiction should be a permissible subsumption result, allowing for the existence of “harmony without difference”. The principle of unity of law and order cannot be simply understood as a system interpretation or a purpose interpretation. As a systematic way of thinking, the minimum requirement of this principle lies in the coherence of good values, that is, the unity of value judgments based on the exchange of good values under the same constitutional order. This principle is not directly related to the issue of subordination in criminal law, and its main value lies in limiting the conclusion of illegality judgment. If a certain behavior is actively advocated by other norms and can be evaluated as conforming to the good value, then criminal law cannot negatively evaluate it.