Abstract: Based on conventional meteorological data, automatic station data and Doppler radar data, this paper analyzes the circulation situation and radar echo characteristics of a hail weather in Dazhou, Sichuan on May 14, 2021. The results show that: The hail occurred under the influence of stepped trough circulation, and the southwest jet stream and low-level convergence provided water vapor and dynamic conditions, while the cold advection from the north and the cold air near the stratum provided the trigger mechanism for the occurrence of hail. The strong updraft caused the strong development of several convective cells, which was the basis of the hail fall. ET, single centroid, the jump to fall of VIL, probability of heavy hail and mesocyclone had good indication significance for hail weather identification and warning.