In view of the inaccurate problem of the basic data used in the life cycle cost analysis of power equipment, the life cycle cost analysis of transmission and transformation equipment based on dynamic data is proposed. Firstly, the characteristics of life cycle of transmission and transformation equipment are analyzed, and the life cycle cost composition and specific calculation formula of transmission and transformation equipment are studied. Next, this paper studies the dynamic data needed to realize the life-cycle cost analysis of transmission and transformation equipment under the background of power information platform. It also introduces the specific process of life cycle cost analysis based on dynamic data for transmission and transformation equipment. Finally, the validity of the method is verified through a case study. This work is supported by Science and Technology Project of State Grid Jiangxi Electric Power Company (No. 52182016001J).