Abstract: With the development of electric power, capacitance of power grid grows faster, short-circuit current increase year by year, many equipments of substation are unable to meet the requirements of safety operation so that these substations require retrofit. Power-off retrofit for center substation will have great influence on the power grid and cost a lot; On the basis of analyzing the characteristic and the key point of live retrofit in 500 kV Jiangmen substation, an approach to solve the difficulties of live retrofit is proposed in this paper to lay the foundation for the safety of substation live retrofit.