To study whether the phased array radar with high temporal and spatial resolution can accurately detect the evolution of heavy precipitation, the quality control of Foshan X-band phased array weather radar (PAWR) data is used to analyze a local short-time severe rainfall that occurred in Nanhai District of Foshan City, Guangdong Province on 4 September 2020. The intensity field and three-dimensional wind field structure of multi-cell storms in Nanhai District from 16:00 BT to 17:30 BT are analyzed, and the relationship between the intensity field, three-dimensional wind field and the precipitation is explored. The results show that PAWR can provide more precise observations of severe convective weather. In the merging stage, the initiation, splitting and merging processes of multiple convective cells on small scale and within short period of time are observed. In terms of the mature stage, the formation process of meso-γ scale cyclone, the structural characteristics of the intensity field, three-dimensional wind field, divergence field and vorticity field during the cyclone convergence period are discussed. In the extinction stage, the structural characteristics of the formation and enhancement process of meso-γ scale anticyclones are analyzed. After the disappearance of cyclone and anticyclone, the convective cells rapidly die out. In addition, based on the statistics obtained from the intensity field and three-dimensional wind field with high spatial and temporal resolution, it is found that the reflectivity factor and horizontal wind speed change significantly in 10-15 min before precipitation and in 5-10 min before the 5 min heaviest precipitation observed by automatic weather stations.The results of this study would have a predictive effect on the monitoring and early warning of short-time severe precipitation, and provide some references for the phased array radar with high temporal and spatial resolution to finely detect the evolution of severe precipitation.