The author of the article has conducted a comprehensive theoretical and legal research of the principles for reforming national security in the domestic jurisprudence. The author has defined the priorities and directions of the reform in the national security sector, and more important – its theoretical and methodological basis. It has been outlined that theory of national security is currently undergoing a stage of active formation and dynamic development. The search for reliable theoretical principles for the organization of the strategic planning system in the national security sector requires its consideration in terms of the application of the most general political and legal methods and tools of the state’s activities, built on the basic principles of complex and systematic nature and aimed at achieving the highest level of the national security. It has been concluded that the formation and implementation of state national security policy in Ukraine is one of the main problems of effective management of a transforming society. Ukrainian political practice indicates that the technology of implementing the doctrines, strategies, concepts and programs of the state policy in the national security sector should objectively integrate all components of political activity of the state and should be based on sound theoretical principles and historical experience. It has been determined that the main purpose of the national security reform is such a quality improvement of legislation and governance in the national security sector, which can provide quality strengthening the protection of key national interests from external and internal, real and potential threats, in accordance with еру current and future needs of society. It may provide the creation or substantial renewal of the activities of existing entities that ensure the national security, a significant change (“reformatting”, “resetting”) of the national security sector in accordance with existing social needs.