The seismic resilience of substations significantly influences the secure and stable operation of the power system. For example, the Sichuan electrical power grid was severely damaged by the Wenchuan earthquake on May 12, 2008, with direct economic losses of tens of billions of yuan. By analyzing the seismic resilience of substations, the ability of substations to maintain their transform capacity under different levels of earthquakes can be evaluated, and their weak point in substations can be identified. Firstly, this paper presents the case study of a typical 220kV substation in China, using a lightning arrester as a research subject to illustrate the process of determining its seismic vulnerability via seismic shaking table tests. Due to numerous uncertain factors affecting the seismic performance of equipment within actual substations, a newly developed approach that combines the pre-existing equipment vulnerability curves to reconstruct the substation equipment vulnerability curve is presented. Subsequently, the reconstructed equipment vulnerability curves were leveraged to compute the transmission capacity of the entire station. This research bears significance in the construction of a robust power grid.