With the continuous developments of science and technology, the technical content of modem equipment is advanced constantly. Tactical and technical as well as combat power has been constantly improving while the economic cost and operational life span have become a major concern of people. This paper at first will analyze economic life-span of equipment, then narrate its cost and benefit, and finally sum up the basic strategy of how to extend the economic life -span of equipment, padding a solid theoretical basis points for the analysis of economic life-span of equipment.