Intelligent Substation as one of the core components converting and managing energy within sturdy and smart power grid system coordinates electricity generation, transformation, transmission, distribution, usage and dispatching. In this paper, a thorough contrast was made between intelligent and conventional substation in terms of technical deployment, investment scale etc. Using life-span cycle technique, the economic analysis of intelligent substation revealed some key factors that dictate economy level. Finally, some rational proposals for decision makes to promote smart grid were given to improve economy of intelligent substation with a reasonable construction scale and sequence.