The invention provides a method for judging whether icing of an electric transmission line exists or not and predicting the icing thickness. According to the wire accumulated ice observation data and electric transmission line icing observation station data recorded by a ground meteorological station, a secondary discriminant equation under Fisher meaning is built for qualitatively predicting whether icing exists or not, a multivariable linear regression model is built for quantitatively predicting the icing thickness, whether each grid point has ice or not is predicted, the icing thickness is predicted, the grid points are guided into Arcgis software, and distribution graphs of existence or inexistence of the wire icing and the icing thickness are obtained through color filling and smoothing. Through the distribution graphs of existence or inexistence of the wire icing and the icing thickness obtained by the adoption of the method, whether the area wire icing exists or not over the next week or the next ten days can be judged qualitatively, and the icing thickness can be predicted quantitatively and finely.