For the complicated electronic system such as active phased array radar, equipment maintenance is one of the core working in the full life circle of product. Over or under maintenance for equipment would affect the usage of equipment, while improving the cost of support. This paper provides one evaluation method for radar power performance based on health management, through parameter attaining and analysis from health management system and knowledge excavation. Thus it can increase the automation and intelligence level of the whole life circle for radar support, and decrease the cost, so as to promote the purpose of equipment operational effectiveness.