It is reported that by the China Electric Power Research Institute is mainly responsible for the State Grid Corporation of key science and technology project "high altitude UHV exchange key project deepening research" passed the inspection. The research results of the project have enhanced the research level of extra-high voltage external insulation and wire electromagnetism properties in China's high altitude areas and will further enhance the field test capability of high-altitude transmission and transformation technologies in China. External Insulation and Wire Electromagnetic Properties Altitude correction methods have important implications for the reliability and economy of transmission engineering designs. The internationally accepted method of altitude correction is mainly applied to the area of ​​2000m and below, and the voltage amplitude is lower than the UHV level. The altitude correction method proposed in this project can meet the air gap under the altitude of 4,300 m at the voltage of 1000 kV and the voltage correction of the insulator and the altitude correction of the conductor corona characteristic parameters, and the technical indexes have been significantly improved. China's high-altitude insulation test mainly rely on high-altitude test base to carry out the work, the site altitude is a fixed altitude. After the successful development of 4000 kV high-altitude long-wave front impact impulse voltage generator, the test conditions of UHV surge voltage at different altitudes are satisfied, which lays a good foundation for further research on power transmission and transformation technology in high altitude area. The project has established the first set of UHV-level corona cage test system in China, which significantly enhanced the research methods of the corona characteristics of UHV splitting conductors at high altitude in China. The research results of the project will be widely applied to the construction of UHV and UHV AC power transmission and transformation projects in China's high altitude areas and will have good economic and social benefits and will further promote the rapid development of China's high altitude transmission technology.