Abstract: The 500 kV transformer has high vulnerability in strong earthquakes. Based on the bilinear hysteretic curve, the spring-friction coupling model is proposed to simplify the friction pendulum isolation bearing. The finite element numerical model of a 500 kV transformer and friction pendulum isolation bearing are established, and the seismic responses of the transformer with an isolation bearing are compared with that of the transformer in the absence of isolation bearings. The results show that there is a risk that the porcelain high-voltage bushing on the transformer in the absence of isolation bearings may be damaged on its root. The spring-friction coupling model is equivalent to friction pendulum isolation bearing in terms of mechanical properties. The friction pendulum bearing has a typical nonlinear feature, that is, after the isolation bearing being installed, the seismic response of the transformer will no longer increase linearly with the increase of the peak ground acceleration. The isolation efficiency of sliding friction pendulum bearing will increase with the increase of the peak ground acceleration. Friction pendulum bearing can greatly reduce the seismic response of 500 kV transformer in the earthquake and avoid the damage of porcelain bushings. And this bearing can also be applied in the isolation engineering in high seismic intensity area.