Based on non conventional observation of ″0185″ torrential rainstorm,primary analysis is made.After synthetic analysis of automatic rain gauge′s every hour data,radar reflectivity factor and infrared cloud image,four primary results are found:1.Enter into sea process and south jet flow are helpful for depression′s development,2.Mass rainfall is mostly caused by cloud′s consolidation,3.Cloud field′s developing phase is also the phase of mass rainfall on the ground,4.It is haphazard that the most heavy rainfall appears in the urban area.