The transmission line in China was iced very seriously in winter by the natural glaze. The corona inception voltage（CIV）of conductors will be reduced after glaze icing

thereby the increased probability of the corona discharge has a great impact on the national economy and life. Although the domestic and foreign scholars have made many researches on icing

most of them are to simulate the ice in the artificial climate chamber

so there are some difference between the conclusions and engineering applications. Therefore a series tests of AC corona inception voltage for LGJ-（70/40

185/25

240/30

400/35）which are the stranded wire to be done after icing the glaze in the Hunan Xuefeng mountain natural icing station. The results show that the ultraviolet photon technology can be used to measure the CIV efficiently and accurately. The icing time increases the CIV decreases continually while the speed saturate. Conductor with thicker diameter will get higher onset voltage than thinners in the same icing time. Higher conductivity decreases the CIV gradually. The conclusion of this paper can provide a theoretical reference for the influence of the natural icing on the corona characteristics of the transmission line.