MICAPS data and NCEP 2.5°×2.5°reanalysis data during the period of 199 6—2005 are used to make statistical research on the activity of southwest vorte x and floodproducing vortex influencing South China. The climatic features such as frequency of vortex activity, genesis, movement track, and intensity during t he genesis and moving process, and its lifetime, average circulation field, and precipitation features are investigated. And the allocation of influencing flood producing synoptic system and its model graph are offered to provide basis for forecasting vortex and floodproducing heavy rainfall in South China.