The prediction of icing on transmission lines is of great significance to ensure the safety of power grids. With the increasingly complex meteorological conditions, this paper proposes a satellite-ground fusion meteorological element inversion based on satellite meteorological and ground meteorological station data, in order to improve the accuracy and timeliness of transmission line icing prediction, relying on the existing icing prediction model. The method optimizes and improves the prediction accuracy of the core meteorological input parameters in the icing prediction model-temperature, precipitation, and wind speed, and then improves the icing early warning accuracy of transmission lines under complex meteorological conditions. Taking a transmission line in Zhejiang as the experimental area, the results show that the improved prediction gives more refined spatial features, which is more in line with the characteristics of this cold wave process. Compared with the observation of the transmission line near Hangzhou, the temperature and precipitation forecast error (RMSE) decreased by 30% and 27% respectively in 24-hour forecast. More importantly, the 72-hour forecast skill did not degenerate significantly compared with the 24-hour forecast. This is important for the early warning on 24-72-hour icing.