Abstract: Based on conventional observation data, FY2E satellite data, fnl 1°×1°reanalysis data and Three Gorges Cascade Dispatch & Communication Center rainfall data, a heavy rain event in the upper reaches of the Yangtze River on 30 June 2016 is analyzed. The results indicate that: under the favorable large scale circulation background, the main impact system of the strong precipitation process are the southwest vortex and low level jet, the maintenance of the subtropical high and the continent high makes the southwest vortex moving slowly, the strengthening of the low-level jet caused the southwest vortex to strengthen, resulting in a wide range of heavy rain; There is no cold air trigger on the ground in this process, it's a strong precipitation process in the warm region in the southwest low-level jet; The upper level divergence zone enhances the upper suction effect, which make the southwest vortex continue to develop.