Abstract:The freezing rain distribution, time evolution and circulation characteristics of the two freezing rain processes that occurred in southern Anhui Province from 4 to 7, and from 24 to 27 in January 2018 were analyzed based on the daily observation data and ERA Interim reanalysis data collected four times a day. The results showed that the onset time of the freezing rain can be estimated approximately by the sudden drop of wind speed to 0 m·s-1 and the fixed wind direction from the automatic meteorological stations, which is earlier than human observation. The two processes appeared in the condition of quasi static weather, but the mechanism for their formation were different. The process during 4-7 January 2018 was of typical “ice melting” mechanism, while the process during 24-27 belonged to typical “super cooled warm rain” mechanism. The surface cold high in the East Asian Continent made the south of Anhui controlled by the northeastern wind during the two freezing rain processes. The cold advection of the northeastern wind developed a cold cushion from the near surface to the ground, and the warm advection from the warm wet air in front of the southern branch trough near 750 hPa was the main cause for the main tenance and development of the melting or inversion layer. So, when vertical distribution of high altitude temperature satisfies the condition for freezing rain, the surface location of 0℃ directly affects the range of freezing rain.