Abstract: Using ground station observation data, ERA5 reanalysis data, and GPCP global precipitation data, this paper takes the regional heavy rainstorm caused by the coupling of the Qinghai–Xizang Plateau Vortex and the Southwest China Vortex on June 4–7, 2019, as an example to diagnose and analyze the coupling characteristics and formation mechanism of precipitation. The results show that (1) the weather process was caused by the combined action of the Qinghai–Xizang Plateau Vortex and the Southwest China Vortex, and the precipitation developed explosively from night to early morning. On June 4, the two vortices produced precipitation centers in the northwest and southwest, respectively, and the precipitation was located in the rear of the Qinghai–Xizang Plateau vortex and the center of the southwest China vortex. The two vortices were coupled in the early morning of June 5–6, and the precipitation shifted to the front of the vortex, strengthening to its peak. The center of the heavy rainstorm was north of Hubei Province. On the night of 6, the two vortices moved eastward toward the sea, and the precipitation area disappeared on land. (2) During the evolution of the two vortices, when the plateau vortex moved eastward from the plateau, the divergence term and the vertical transport term enhanced the positive vorticity of the basin. At the same time, as the low-level convergence configuration strengthened, the southwest vortex was further induced to develop in the basin, and precipitation occurred in both vortex regions, providing a key dynamic condition for the subsequent coupling of heavy rain. (3) During the coupling development, the centers of the two cyclones at different heights merged to form a deep convective system, which generated strong positive vorticity columns and strong convective instability, accompanied by vertical upward motion and secondary circulation development. The southwest monsoon and the southerly airflow outside the subtropical high transported abundant water vapor to the front of the vortex, and under the synergistic effect of deep shear convergence and strong dynamic uplift, this process eventually led to heavy rain.