Based on the real-time observation data on 500 kV high voltage transmission lines in Hubei area in February 2008 and January 2009,MICAPS conventional meteorological data and NCEP reanalysis data,this paper studies the synoptic systems and meteorological conditions during the two wire icing processes.Results show that the deep low pressure trough at 500 hPa and low vortex with shear line at 850 hPa,which is close to Hubei area,have positive effects on ice thickness during the two icing processes.The air temperature and wind velocity play a leading role in the initial stage of the two icing processes.