A new intelligent strategy of transformer， circuit breaker， arrester for extra-high voltage smart substation， and their intelligent component configuration as well as the implemented mode of integrated fault diagnosis are proposed. Analysis， evaluation and prediction of transformer， circuit breaker and arrester， etc. monitored equipments are implemented by sharing information and synthesizing data from main equipments so that the fault property， type， degree， cause and trend can be judged. Suggestion for removing failure is put forward so as to provide latest reference information for operating personnel and maintainer. Research results have been successfully applied to modernization of 500 kV smart substations.This work is supported by State Grid Corporation of China.