Through the introduction of 5000 series Defense Acquisition Management Procedures and evolution and development process of the U.S. Department of Defense, combined with the review of typical major aviation weapon system program development process，the causes and trends of evolution of defense weapon system research and development management procedures are analyzed according to The Qian Xuesen School of Systems Engineering, Philosophy of Engineering, Theory of Engineering Knowledge and other viewpoints. This paper discusses the basic attributes of the research and development of national defense weapon system such as complexity, knowledge, systematicness and integration, call for the implementation of the strategy of reducing risks by knowledge accumulation in the research and development of major weapon system, and promote the in-depth application of knowledge-based equipment development acquisition methods.