The invention discloses a lightning early warning method based on radar data, and the method comprises the following steps: S1, detecting radar data, classifying the radar data, and removing repeated data; s2, extracting historical thunder and lightning data and thunder and lightning monitoring data of the radar monitoring area; s3, lightning simulation is carried out according to radar monitoring data and historical data; s4, performing grade judgment on the simulated thunder and lightning, and performing early warning in different modes according to different grades; s5, monitoring thunder and lightning occurrence time and thunder and lightning grades after early warning, and recording monitoring data; and S6, comparing the monitored thunder and lightning occurrence time and thunder and lightning level with early warning data, performing difference degree calculation, and evaluating early warning accuracy. Thunder and lightning early warning can be effectively performed, and evaluation of early warning accuracy is facilitated.