Meteorological factors play an important role in the stable operation of transmission lines, which should be considered in risk assessment. This paper presents a method of transmission line meteorological risk early warning and protection. Considering the temporal and spatial power generation forecasting, equipment health and reliability assessment, probabilistic load forecasting and other aspects, a refined meteorological risk model is established, and a new risk measurement standard is proposed based on Meteorological hazards, grid vulnerability and post disaster recovery cost. In addition, aiming at the restoration of load interruption and the alleviation of power congestion, the online warning and defense strategy of meteorological disasters is proposed. Finally, the proposed method is tested and analyzed in the simulation to verify the effectiveness of the method.