Life Cycle Cost (LLC) management takes long-term economic benefits as starting point, and the whole process from design to retirement is fully considered in order to minimize costs. The development of LCC theory is analyzed firstly in this paper. Then, combined with condition-based maintenance strategy, the LCC model and sensitivity analysis of the key equipment such as transformer, switch, high voltage cable are studied. Finally, the key data in the operation and maintenance process is identified to give reference to power system life-cycle management system building.