Using conventional meteorological data，small and medium scale encryption station data and 1×1°fnl reanalysis data，this paper analyzes a torrential rain process which occurred in June 19，2010. The results show that the large range torrential rain process is the result of the multi scale system impact. The development and movement of synoptic scale system are influenced by the stability of zonal circulation and distribution of subtropical high belt. Under the favorable large scale circulation background and excited the activities of the medium and small scale convective systems，it triggered the convective instability energy release，which resulted in more heavy rain belt mesoscale convective cloud cluster and corresponding with the mesoscale rain cluster of organized activities. This is the main reason for the heavy rain occurred.