Abstract: Based on conventional observational data, ERA-5 reanalysis data and FY-4A satellite data, the mesoscale environmental characteristics of a heavy rainstorm in Qinba Mountains caused by the induced cyclone of northwest vortex (NWV) on August 6—7, 2020 are studied, and the development process of the induced cyclone is quantitatively analyzed by using Potential Vorticity (PV) and Okubo-Weiss (OW) parameters. The results show that the heavy rain process was caused by the Mesoscale Convective System (MCS) under the action of the cyclone induced by the northwest vortex. The heavy rainstorm was basically located in the cold center of the cloud top brightness temperature of the mesoscale convective cloud cluster and the large value area of the brightness temperature gradient on the side of the northwest airflow. Before the formation of the induced cyclone, the northerly airflow in the rear of the NWV and the southwesterly airflow in the periphery of the Western Pacific Subtropical High (WPSH) formed a mesoscale shear line, which triggered some unorganized convective cells in the Qinba Mountains with low precipitation. After the formation of the induced cyclone, the water vapor transport, the positive vorticity, strong convergence and updraft at lower troposphere in Qinba mountains were significantly strengthened to trigger the convective instability, resulting in multiple β and α- Mesoscale convective cloud clusters merged and developed into MCS, which brought large-scale heavy precipitation in the process of slow eastward movement. The induced cyclone was a vortex circulation formed by the downward transmission of high vortex caused by the 500 hPa trough and the increase of cyclonic vorticity caused by the large value of 700 hPa OW under the favorable high and low altitude situation. The northerly airflow behind NWV and the cyclonic movement of the southwest airflow around the WPSH were strengthened, and the vertical coupling of 500 hPa PV and 700 hPa OW parameters could make the induced cyclone develop into a strong vortex system, which led to the occurrence of heavy precipitation. When the PV and OW parameters decreased at the same time, the cyclonic circulation structure of the induced cyclone was difficult to maintain, and became a part of the NWV after weakening to the shear line.