A seismic safety performance evaluation method for 1100kV porcelain arresters with dampers is put forward based on the stochastic earthquake model. The dynamic performances of 1100kV porcelain arresters with and without the new type lead dampers are analyzed by establishing corresponding finite element models. And the mean and standard deviations of the random seismic responses of the arresters with and without the new type lead dampers under artificial seismic waves synthesised by the stochastic earthquake model are gained. Then the seismic assurance coefficient of the arresters is calculated by FOSM

and the fragility curves of the arresters on second-class site are achieved. Evaluation results show that the anti-seismic fortification grade of 1100kV porcelain arresters with the new type lead dampers can be increased by one rank.