Aiming at the frequency characteristics and distribution law of corona noise of transmission lines, three groups of 1000 kV UHV AC transmission lines were selected in Shandong Province, China. Continuous monitoring and fixed-point monitoring of corona noise were carried out to obtain the spectrum curve of corona noise. The spectrum curve and distribution curve of transmission lines and the overall A sound level distribution of corona noise were analyzed. The results show that the corona noise of transmission lines is medium and high-frequency noise, and its spectrum reaches the peak at the central frequency band of 800 Hz. The lateral distribution of the noise amplitude of the transmission line decreases with the increase of the outward extension distance, and the attenuation is close to the background noise at the outward 40 m, and the overall A sound level decreases by about 5.01 dB.