Discipline inspection and supervision as a first-level discipline contains unique theoretical logic, which is also the theoretical support for its standing under the category of law with other first-level disciplines. At the institutional level of discipline inspection and supervision, on the whole, it has gone through the "discipline inspection" stage dominated by intra-Party supervision, the "supervision" stage in which intra-Party supervision and administrative supervision are parallel, and the "discipline inspection and supervision" stage in which intra-Party supervision and state supervision are integrated. The development context of the three stages clearly presents the general trend of the development of discipline inspection and supervision, that is, the integration of discipline inspection and supervision. The evolution of the system from "discipline inspection" to "supervision" and then to "discipline inspection and supervision" reflects the growing maturity of the concept of national governance with the joint efforts of the Party and the law, laying the foundation for the discipline construction of discipline inspection and supervision. Discipline inspection and supervision, as a first-level discipline, has its special theoretical essence, theoretical significance and governance value. The three together build a theoretical gradient of discipline inspection and supervision disciplines. Disciplines such as traditional law, political science and Marxist theory are difficult to fully reflect the connotation of the new era of discipline inspection and supervision. Only by positioning discipline inspection and supervision as a first-class discipline and establishing a special theoretical system, can the theoretical essence of discipline inspection and supervision be fully explained. The significance of the first-level discipline of discipline inspection and supervision is that it is an innovative cognition of state power, which helps to promote a smoother relationship between the Party and the law, and build China’s independent discipline system, academic system and discourse system. Discipline inspection and supervision, as a first-level discipline, can show higher governance value, help to better transform the advantages of the anti-corruption system into the effectiveness of supervision and governance, and also open up an innovative model of national governance to provide the world with Chinese solutions. The theoretical category system of discipline inspection and supervision as a first-level discipline includes the cornerstone category and the core category. The fundamental purpose of discipline inspection and supervision is to ensure that the Party is in power for a long time. For this reason, the supervision mode should be transitioned from "binary supervision" to "monopoly supervision" to achieve more authoritative and efficient supervision. This is the cornerstone category of discipline inspection and supervision. Anti-corruption under the rule of law is the key means to consolidate the Party’s ruling position. Adhering to self-revolution as the center, striving to achieve high-efficiency anti-corruption, whole-process anti-corruption and full-coverage anti-corruption is the core essence of anti-corruption under the rule of law, which also constitutes the core category of discipline inspection and supervision. The next step in the construction of discipline inspection and supervision disciplines should focus on the division of secondary disciplines, the design of the curriculum system and the planning of talent training, and at the same time do a good job in the docking of practical directions to promote the efficient transformation of research results.