A rapid, high-amplitude global climatic warming would speed global water cycle and strengthen rainfall and evaporation. Mean temperature in 1990s increases 0.2~0.8℃ comparing on the temperature between 1951 and 1980. High temperature increases in the Yangtze Delta. Annual precipitation increases more that 5%~20% in 1990s than the value between 1951 and 1980. At the Yangtze river catchment 5 heavy floods were happened in the 1990s. As the Yangtze river catchment plays an important role in the economic development in China, potential loss to floods increase very quickly. Based on the value of production in 1998, potential losses will be 58 900, 5 500, 7 000 and 19 600 million US dollar if the 1954, 1991, 1996 and 1998 floods would be happened. Based on regional climate model developed from National Climate Centre, increase of greenhouse gases like CO₂ will lead to increase of about 2.7℃ of annual mean temperature in the Yangtze river catchment,  it is projected to estimate the increase of 10% precipitation and 37% runoff. It is conclusion that the possibility of heavy floods like the types of 1998, 1954 and 1870 would happen in future as the impact of climatic warming and increasing urbanized area due to fast economic development.