Abstract:The natural icing of overhead lines in southern region is a maintenance problem and disaster prevention subject, and it is urgently needed to improve the prediction and warning ability of overhead line icing in this area. After the analysis to the worldwide icing prediction model of overhead line, this paper summarizes the icing levels method and icing grading division in refined meteorological elements based on the statistics-empirical knowledge, furthermore coupled with the terrain and meteorological factors of natural environment to construct the corresponding icing grading model with stronger generalization ability, thereby establishes the efficient forecast and warning mechanisms of overhead line icing. The 2-year application validates that this model and working mechanism can accurately predict and warn the icing state of overhead line.