The icing on electric wires is a complicated physical process affected by all kinds of meteorological factors. The theoretical frame of the model for icing and the main influencing meteorological factors on the increase of icing accretion on electric wires are analyzed, and the moisture transportation index related to ice growth is built. The meteorological forecasting model of icing accretion on electric wires is proposed. Using the icing and common meteorological data from 1951 to 2010 from meteorological observation stations of Guizhou Province, the empirical function of the efficiency factor in the model is fitted, and compared with the existing icing model. The results indicate that this model has better maneuverability, and the fitting results of the model for historical data are satisfactory.