This paper proposes a novel appoach which can assess the system technical maturity for use in Defense R&D Program reviews. As the weapon systems become more complicated, the success and effectiveness of R&D outcome heavily depend on the application and tailoring of systems engineering process and methods. It is a difficult task to assess the system readiness level(SRL) of the system being developed. A system-focused approach for managing weapon systems development and making effective and efficient decisions during the development lifecycle is critical to ensure the success of the program. The proposed weighted average SRL can facilitate the system technical maturity assessment without expending heavy work load.