As an important doctrine in criminal law theory, Legal Interests Theory gradually aroused the attention of the criminal law field, and was a concern for civil law and other departments of Law. In this paper, the theoretical value of the Legal Interests Theory will be considered and the applicable dimension will be expanded. The opinions of this article include: The Legal Interest Theory of great value is not only on the Criminal Law, but has a value of jurisprudence. The generation process of legal interest is a expression process of legal interest by the legal mechanisms. Legal interests of department law are combination by Legal interests and Law Mechanisms. After appropriate transformation, Legal Interests Theory can be applied to other departments of the law, including Civil Law, Environmental Law, and other areas of the law.