The measured data of GIC in Guangdong Lingao 500 kV power networks during the several magnetic storms at the peak of 23rd Solar Cycle, the GIC calculation results of 2010 750 kV planning power grid in Shanxi, Gansu, Qinghai and Ningxia, the structure and characteristics of power networks from 500 kV to 1 000 kV, and super magnetic storm in 1859 are analyzed in this paper. Through the analysis, the possible impacts of extreme space weather on the future UHV, large-scale power system security in China are discussed, and the research suggestions coping with the strong solar storms are proposed.