Abstract: Study on the physical process of hail cloud development is of great significance for further understanding of hail cloud, summarizing the experience and improving the level of artificial hail prevention operation. Using Doppler radar data and MICAPS conventional observation data, a multi-point joint hail prevention case on 1 July 2020 in the eastern agricultural area of Qinghai Province is analyzed, from the aspects of synoptic situation, environmental conditions, echo evolution and effect inspection.The result shows that the combination of multiple convective cells on the radar chart is beneficial to the further development of hail clouds. After the operation, the maximum echo intensity, the 30 dBZ echo top height, and the CR≥45 dBZ echo area were significantly reduced; 5 minutes after the operation, the average rainfall in the operation area increased sharply. During the hail cloud development, the multi-point joint over-seeding operation in front of the moving direction will exert positive effect on hail prevention.