The electric design of valve hall is the key and difficult point in the design of converter station, especially for UHVDC converter stations in areas with high seismic intensity. The corresponding improvement and optimization should be carried out on the basis of conventional electric layout and connections to meet the anti-seismic requirements. ±800 kV Xinsong converter station is located in the 8 degree earthquake area, and the electric equipments, electric layout and connections are fortified according to 9 degree (0.4 g) earthquake intensity. Based on the analysis of the electric equipment seismic calculation results in the valve hall, the electric layout and connections of the valve hall are optimized. On the basis of electrical and mechanical characteristics being satisfacted, special fittings connection schemes such as horizontal Z-knee busbar fittings and vertical Z-knee busbar fittings are adopted. The key electric circuit of the valve hall is seismic decoupled by the special fittings connection, which ensures the safe operation of the electric equipments in the valve hall under the earthquake condition.