Aiming at the electromagnetic interference problem of UHV transmission lines on civil aviation communication, navigation and monitoring stations, the article carried out a 1000KV UHV on-site electromagnetic environment test, and then used the principle of space electromagnetic wave propagation to calculate the interference of 1000KV UHV transmission lines at the evaluation point based on the test results Signal field strength. Combined with the electromagnetic environment requirements of civil aviation communication, navigation and monitoring stations, the protection distance of 1000KV for the localizers involved in the example should not be less than 909.6m, and the protection distance for glide beacons should not be less than 350.9m.